Okay, here are my Final Thoughts on how to buff/change Lil Mac, in order of most to least importance:
Credit to SDoom for many of these
-Reverse the way the KO punch meter builds
I've already spoken more than enough on this topic, but as a summary: Making him fill the meter more from damage dealt and less from damage taken would promote you outplaying your opponent and would reward you for being smart and being a good player. This would make Mac a much better character with more potential, meaning that he has more ability to be a better character in the hands of a good player, rather than having a tool for people who are getting outplayed to get lucky victories. Would you rather be able to reliably 2-stock opponents as a reward for becoming so good with a character, or get lucky shots/victories for relying too heavily on one option?
-Reliable ability to jab lock
After labbing with Little Mac for a long time, I can safely say he needs this likely the most. Currently you have to hyper-mindgame
your opponent and achieve TaS level perfection to get a footstool and follow up with the Dair, and only in very limited(And non-guaranteed)ways. Anything to change this would be an incredible buff, having a throw confirm into a tech situation and subsequently jab lock, another move with locking capabilites, have Nair true combo into footstool, ect. I'd say the best option is to give him another move with Locking capabilities, likely a simple Jab1. This would enable him to follow his opponent after an F-tilt or Side-B(Possibly, maybe just Ftilt), or really any of his moves at low-mid% and get humongous followups out of them. This would also give his custom UpB, Rising Smash, viability with its ability to kill at around 55-65%, which also happens to be the percentage where most of Macs moves force techs. Overall, if he had more ability to jab lock, all of the custom combos that have been cropping up with his Locks would all be much more possible and common, giving him tremendous viability.
-Give down-pivoted F-smash more shield damage;Enable a full charge to break a full shield
This one's self explanatory, Mac has poor throws and pitiful grab range, making him lack a solid anti-shield option. Giving this move the ability to more heavily punish shields, especially when paired with his early kill moves.
-Return aerial side-b to pre patch glory
Everyone in this thread has beaten this into the ground already. No reason for it to have gotten nerfed other than salty For Glories whining about losing to Little Mac on day 1. This could also give it some good OoS properties to combat spaced aerials that his other OoS options can't reach.
-Increase Jab Hitstun(?)
Possible nerfs to balance:
-F-tilt&D-tilt startup&cooldown increase by 1-2 frames
We wouldn't miss those frames much, they'd likely still serve their purpose, but just a tad less quickly. As long as D-tilt can still combo into KO punch and RAR Nair it should be fine.
-Slight decrease in roll speed
He doesn't really need all that roll speed too much, its a bit excessive. A few frames decrease won't be argued against I'm sure.
-Possible extra small nerf. Can't think of anything else right now.