So I'm quite torn.

I'm planning on playing a Custom Linage Mercy Monk (Mobile Feat at Lvl 1)

Its point buy and i'm tossing up what I think are 2 options. This will be a Waterdeep Dragon Heist into Mad mage so theoretically we should plan for 20

Idea one

Stats are

Str 10

Dex 17 (+2 from Custom Lineage)

Con 13

Int 10

Wis 15

Cha 8

Lvl 4 I would take +1 Dex +1 Wis to even those out then at lvl 8 id take Crusher to boost my Con to 14 for an even score and then boost dex to 20 followed by Wisdom Boosts the next 2 ASI's

Option 2

Stats are

Str 8

Dex 17 (+2 from Custom Lineage)

Con 14

Int 10

Wis 15

Cha 8

Lvl 4 I would take +1 Dex +1 Wis to even those out then at then lvl 8 id max out Dex then next 2 ASI's id max out Wis leaving me with that one Feat to take at lvl 19 which id just take lucky or something like that.

Each has its Cons and Negatives

The Crusher Route means I max my Dex and Wis much slower but as a payoff I get the ability to slap people around a bit if I feel like it and if I score a crit we all get free advantage. I also have 10 Str meaning that I can clear 10ft gaps with my jump distance (something that we learned in TOA can be important) and a slight boost to my Athletics which is a decently common skill in our games

The non-Crusher Route means I get to max my Dex quicker and my Wis and have a bit more HP up to level 8 when it evens out.

What does everyone think. I know my DM and he likes to throw hard fights at us so somewhat optimal play is usually required.

Minmaxer makes me think the second is better. But the first sounds like much more fun and is a good build. It isn't weak at all and it does what you want as a mercy monk really well. I would go the first as utility and jumping is very useful. Maxing wis later isn't that bad but crusher seems like fun and gives you more wiggle room

Better plan: 17/15/15 Dex/Wis/Con.  Strength 10 and Intelligence 10 each do basically nothing for you (and Strength 10 does more than Intelligence 10).  Plan from there.

I cant do it. I cant do the 3 8s. I've tried it before and having that many -1s in my skills just feels horrid. From a completely min/max standpoint yes that is superior with option 1 but I just cant

Quote from Jiendo >>

I cant do it. I cant do the 3 8s. I've tried it before and having that many -1s in my skills just feels horrid. From a completely min/max standpoint yes that is superior with option 1 but I just cant

Then you might be better off avoiding a MAD (multiple ability dependent) class - a SAD (single ability dependent) class can afford ability points to burn on other things.  These are MAD:

• Classes:
  • Monk, unless you "fix" it with Astral Self - this is not a real fix, as you need to be on the front line while naked, so Dexterity remains a must unless you're a Tortle.
  • Paladin, unless you fix it with a multiclass dip into Warlock (Hexblade) or get access to Shillelagh somehow
  • Ranger, unless you "fix" it with Druidic Warrior (Shillelagh/Magic Stone) - this is only a partial fix, as it costs a bonus action; Magic Stone also cuts your ranged damage from 1d8+mod to 1d6+mod and needs re-upping midfight, and Shillelagh can't fix reach weapons, if you were building into a glaive or whatever.
  • Warlock with Pact of the Blade, unless you fix it with Hexblade
  • Artificer, sort of; only two subclasses (half of the four they have) can't weapon attack with their Intelligence, and neither of them has any particular need to make weapon attacks, and it's also fixable with a gauntlets of ogre strength infusion, but Artificers do have access to some abilities - some infusions and some spells - that rely on weapon attacks to be relevant.  You can just not take those abilities, though.
• Subclasses:
  • Fighter (Eldritch Knight) and Rogue (Arcane Trickster)
    • Does not necessarily need to fix being MAD, as you can avoid spells that care about your spellcasting ability modifier.
  • Bard (Swords, Valor, or Whispers), unless you fix it with Hexblade or Shillelagh or Magic Stone
  • Cleric (any domain with Divine Strike), unless you fix it with Shillelagh or Magic Stone (both of which are very difficult for you to get - they're not on your spell list); you can also swap Divine Strike for Blessed Strikes, which is a lot weaker than Potent Spellcasting but can patch the issue, particularly if you only cast 0-1 cantrips per round.
    • Does not necessarily need to fix being MAD, as you can avoid spells that care about your spellcasting ability modifier, and use your Channel Divinity in ways that avoid your modifier, but you'll have fewer spells prepared.
  • Druid (Spores), unless you fix it with Shillelagh, which you can trivially take.
  • Wizard (Bladesinger), unless you fix it with a multiclass dip into Artificer (Armorer or Battlesmith) or Shillelagh or Magic Stone, neither of which are on your spell list.
    • Does not necessarily need to fix being MAD, as you can avoid spells that care about your spellcasting ability modifier until later - Bladesingers uniformly want Dexterity and Intelligence unless they're tortles, but you can grab Dexterity and buffs first, then Intelligence and offensive spells later.  Avoiding Int does mean you'll have fewer spells prepared.

So Monks are the "MADdest" - they need Dexterity and Wisdom and have the most difficulty of anyone fixing this (and absolutely everyone needs Constitution).  If you want ability score modifiers handy for being more skilled, I highly recommend against being a Monk - they're simply not designed to be good at that - or if you must be a monk, being an Astral Self Tortle so you can dump Dexterity.

If you're starting at level one with mobile, which I agree is a good move, it is actually more optimal to for variant human. This way you can start with 16 dex and wis and have an AC of 16 from level one. You can go for +2 dex at level four and be in the same exact spot your custom lineage builds are.

I agree with Quindraco about the starting stats and that you should go for 8/15/15/8/15/8 if your goal is to pick up crusher. Most characters have a pretty limited scope of skills they are good at and that's okay. Monks don't play into the skillmonkey role all too well anyways. Good dexterity and wisdom covers a wide swath of skills as well, so there are plenty that you will excel at.

While i can see 100% about the 3 15s 3 8s spread and i just threw it into a sheet....yeah youre right all i really loose is the int skills as i took athletics as a prof.

i disagree with vhuman over custom lineage

Id rather take the odd stats to lvl 4 and get dark vision over having the 16s at lvl 1 with no dark vision. 1-4 it MAY be better if there's no dark areas but at lvl 4 custom lineage is superior 

My experience with darkvision is that it's really good for one person to have it, and even better if everyone has it. But if even one person doesn't, you will need light which drops the value considerably.

Remember that you have Step of the Wind for jumping, so STR 10 is not super vital.

I'd rate the value of Crusher based on your party composition. It can be very good if you can push things into a damaging zone or slide one more guy into the area of an incoming Fireball.

Our Party ATM is another monk without crusher a wizard and a Sorc so definitely a good team in terms of throwing things on the ground to knock em into

Quote from Jiendo >>

Our Party ATM is another monk without crusher a wizard and a Sorc so definitely a good team in terms of throwing things on the ground to knock em into

 Gasp double monk and very nearly double wizard?  This is Final Fantasy 1 level antics, I approve.  Having the highest strength in the party be probably 8 and maaaaaybe as high as 11 is bound to be entertaining.