So I have this one player who is becoming "that person" at the table. They are a spotlight hog, and quite obnoxious at times. They constantly play characters that are way extra. This particular PC is an old crotchety wizard. They were walking towards the Dripping Caverns in Storm King's Thunder tonight and this PC kept ranting loudly, as they tend to do. Two things that bothered me here were that 1) it prevented any players a word in edgewise to plan or discuss tactics; and 2) it alerted the goblin patrol. 

They dealt with the patrol easily enough and proceeded into the mouth of the cave. This PC kept talking. The player said, "X keeps rambling, loudly" before anyone else in the group had time to act, "OK. You have alerted the whole goblin clan to your arrival. You are faced with 2 Ogres and 7 goblins." Unbeknownst to them one goblin went to warn the leader. This guy is in the midst of feeding the villagers/prisoners to his pet rats. There is nothing keeping him from executing the whole village before turning his attentions to what remains of the party after facing off against an entire goblin clan plus their two Ogres. 

IF the party survives, they will have no forward progression to take them further into the campaign as the quest-giver is among the villagers.

Sure, u could home brew my way out of this, but I may not. I have sent the player responsible a message and have gotten no reply. Do I move forward letting the consequences of their actions play out or do I retcon and fix this? What would be a better approach? What would fix this player's problem habits best if this talk doesn't work?

Btw, game picks up again tomorrow. It was cut short due to Roll20 issues. 

Uninvite that player?

How are the fellow player characters handling this wizard that seems hells-bent on getting them all killed? Could a slightly-meta-nudge help facilitate a bit of in-game resolution? 'As you approach, it becomes painfully obvious as the wizard's constant mumbling echoes around the mouth of the cave, that he's likely to alert every last goblin in the place, unless one of you wants to do something about it?'

Ultimately, you need to evaluate whether this is an in-game character issue, or an out-of-game player issue. Troublesome players can be a nightmare, but continually enabling their behaviour by letting their obviously derailing actions play out in game isn't going to solve the problem. Because the reality is, if they're trying to be disruptive, get attention, or derail the whole thing, then they probably don't care.

You might think you're giving them their 'just-deserves' - but you're really just delaying what needs to be resolved. The issue isn't with the character, it's with the player - and so it needs an out-of-game solution.

Quote from Chequers >>

Ultimately, you need to evaluate whether this is an in-game character issue, or an out-of-game player issue.

That's a false dichotomy; the player creates the character. The important question is whether the action is accidental (sometimes someone comes up with what seems like a neat idea and fails to consider its effects on the game) or deliberate. The first can be resolved by gently pointing the problem out; the second doesn't have good solutions (I was serious about suggesting uninviting the player, though; often ejecting the player is less bad than other options).

Just remember that whenever you have a player you feel is hogging the spotlight, YOU as the DM have control of that spotlight.  Ignore the offending player and lock eyes with another player who wants to role play and focus your attention on them.  The table will follow suit.  He'll get the message.

In this particular situation I would have focused my undivided attention on the players trying to plan their tactics, and prompted them to continue.  If the bothersome player continues ranting it is perfectly ok to wave your hand at him and say "hang on a minute".  Also would have glossed over and ignored the fact the goblins probably heard him.  

controlling the spotlight is the key to controlling your table.

Quote from Pantagruel666 >>

Quote from Chequers >>

Ultimately, you need to evaluate whether this is an in-game character issue, or an out-of-game player issue.

That's a false dichotomy.

I'll reword: 'Can this be resolved in-game through character interaction? Or is this an issue with the player themselves?'

If the player isn't intending to be a nuisance, but has simply made a character that's causing troublesome scenarios in the game, then that's potentially resolvable through in-game play.

If the player has no interest in playing the game, but is looking to cause trouble, derail the game, and make everyone miserable - then that's an out of game issue, resolvable only by speaking to the player; or as you've suggested, ejecting them from the table.

I think we're essentially making the same point.

If you can get through to the player and get them to acknowledge they might be ruining things for the party, you can improvise your way out of it. If there’s no response, talk to the other players and see what they can live with. Present it as “Your characters would know this, but I need to confirm out of game that the wizard’s incessant loud talking is giving the goblins every opportunity to prepare for your arrival, and is likely to get everyone killed. And even if you survive the army of goblins, there may not be anything left for you to find or save. Like, literally the end of the plot by death or inability to move forward. As players, out of game, is that an acceptable consequence? I can save the campaign, but the Wizard may not learn. If I let things play out according to straightforward logic, you may not be playing with these characters after the next session. If he were the only one at the table, this would be an easy choice, but you all are playing, too” 

OK, outside of the problem player issue, let’s see if we can improvise fun ways around your impasse. You say the chief is feeling villagers to the rats as they approach and there’s nothing stopping him from killing the whole village as a middle finger to the meddlesome adventurers.  Which would kill the quest giver for the continuation of the plot.  Let’s change something there. Create a reason to parley with the party.  What could the chief want that the adventurers could give.  He might be willing to trade villagers to get what he wants.  This could save the quest giver.

OR create a turncoat goblin NPC who has secret aspirations of taking over leadership. The chief left to deal with the intruders himself and left the traitorous officer with the instructions to kill them all. Turncoat keeps some villagers alive as a bargaining chip to get you to leave him and those loyal to him alive so he can take over the tribe.

OK, this sounds like a troublesome player, however, it is not the player who has decided that the entire adventure will "fail" if the players doesn't solve this encounter in a certain way or manage to save the villagers in time. That is your (or the module's?) decision. You have control of wether this adventure really hangs on this.

I would have brought the entire tribe down on the players. Make sure you inform them the reason - they all heard the wizard, and they decided to strike. This means they will be able to set an ambush and prepare, and that the fight will quite possible not go in favour of the players. That's how you teach a lesson, just remember you at some point not to late in the battle should make sure the PLAYERS understand they will most probably loose due to bad tactics, and allow them to rather try to escape to try again another day.

That means you'll either have to find a way to save the quest-giver, or invent a new one if you really need one.

I'm going to imagine this person is really sucking the fun out of the game for the rest of the party. Which is counter to why we play. Either get him to play nice, or boot him from the group. 

In the meantime, wizard falls in a trap, party finds some way to escape the pursuing goblins. This sends a message, and allows the rest of the group to have fun.

Why would the goblins immediately kill prisoners? Would they not be more likely to use those prisoners as hostages or meat shields?

I've just checked the adventure and it even says that the party can just go in and kill all the enemies to win the freedom of the captives, or could just negotiate with the goblin boss who has a strong sense of self-preservation.

So the whole "all prisoners must die" thing is something you are inventing.

I'm not condoning a troublesome player, but you're the one inventing a harsh consequence that isn't in the adventure. Nothing in the adventure says they must be stealthy or prisoners die.

So far all this player has done is avoid a stealthy approach in a situation where stealth, while useful, isn't necessary. I don't see that as a troublesome player.

If you want to continue as-is, you could "conveniently" keep the quest giver(s) at the back of the feeding line, and however long it takes them, should the party survive they arrive "just in time" to interrupt the feeding process, letting the plot-specific NPCs survive, with maybe an extra villager or three.