Rogue Fixed? Or Broken?

I was thinking about how the Rogue is often regarded as the weakest of the Martial classes. I wonder if they truly are a Martial class, or if they are actually a "Skill" class? And perhaps they are supposed to be weaker in combat than the Barbarians, Fighters, Paladins, and others? 

But let's assume they ARE a Martial class. Let's assume that Rogues DO need a boost to compete with Fighters, et.al. Given those assumptions, I had an idea for a "fix". We address the Rogue's damage and defense with two simple adjustments:

First, on defense: let's give Rogues their proficiency bonus added to their Armor Class when wearing only Light Armor and no shield. Leather and Padded Armor give a base AC of 11, and Studded Leather gives a 12. Most players will have a +3 to Dex in early gameplay. Some may have a +4. That gives an AC range of 14 to 16. Which is ok, but not great. Adding Proficiency to this will increase that AC range to 16 to 18. And it will help Rogues have an AC that scales. Dexterity caps at +5 until Epic levels, so, excepting for magic armor, Rogue AC caps out at 16 or 17. With Proficiency, that would increase as they level, until they maxed out at 22 or 23 (11 or 12, +5 Dex, +6 Proficiency at the highest levels). Obviously, magic armors would boost this by an additional 1 to 3. But that still isn't unreasonably high, if you consider some of the ACs achievable by Artificers, Paladins, Fighters, etc, when they have full plate plus a shield- especially if those are magical. But idk... maybe this is too much. And of course, one could easily argue: if Rogues get Proficiency added... why doesn't everybody? I mean, they're all proficient at wearing their respective armors, so... why not? Yeah, idk. Because Rogues need the help more, I guess?

Anyway. Offense: quite simply, give Rogues a second attack at level 5 like every other Martial. And let them use their Sneak Attack on both attacks, so long as both attacks meet the normal prerequisites. It should be made clear thst Rogues could only apply their Sneak Attack to attacks using the Attack Action, and not to any attacks made using their Bonus Action. And maybe we'd need to eliminate their ability to Sneak Attack on their reaction, to balance things out. Maybe not. Then, at a higher level- say, level 15 maybe- Rogues could then also Sneak Attack on a Bonus Action attack for up to 3 Sneak Attacks on the Rogue's turn. Although, that might be getting too ridiculous.  You'd be looking at like 24d6 (72 average damage, with potential for up to 144) at level 15. And then if they were to crit... well that's just broken. So maybe not with the 3 Sneak Attacks. 

At mid level tiers, we'd be looking at 6d6 to 14d6 of Sneak Attack damage, assuming 2 hits with 2 Sneak Attacks on a turn. That's not actually that crazy high, considering Paladin's Smites, Barbarian Rage damage, Fighter's multi-attack & Action Surge, etc. But then again, maybe it IS too crazy-high damage. Idk. Probably. There's also the concept of increasing the potential pool of d6's available for the Rogue to spend on Cunning Strike options- as well as the ability to apply two Cunning Strike options in one turn. And then FOUR at level 11. And that is another whole can of worms.

Anyway. It was just a thought that I had, and I thought it'd be interesting to see people tell me how broken this probably is. But also to see if anyone has other ideas, or adjustments to these ideas.