Incoming wall of fucking text be ready.
1) Better spectator tool.
2) Support from developer.
a. Put big matches on the main menu and people-random pubbers who have just launched tf2 and never heard of comp-can 1 click to spectate.
b. Highlander and 6v6 ques. Basically do exactly what CS:GO does. Each player has an individual rank and that is changed by wins and losses. You don't get matched up with/against players much better or much worse than yourself. Bring in TF2s unique mentorship mechanic (the coach a new player thing) and high level players (like high open and up) could be placed 1 on each team of a low level matchmaking game.
c. Make basically every "pro" map the stock. Change valve server rotations away from payload and towards 5cp and koth. This is not to say there should be no payload valve servers, just the rotation should favor somewhat heavily 5cp and koth maps.
d. Just delete arena mode please.
3. Buff medic. Give him an LG or something that has a really high skill ceiling (like the xbow) but that actually gives him a hope in hell of winning a 1v1 fair fight (not like the xbow).
4. Raise the skill ceiling and lower the skill floor for "pub" classes:
a. Lower the DPS of heavy. Make bullets have a tighter spread. Balance these such that if you track really well you can get the same DPS as the heavy has now (because less bullets are missing).
b. Pyro airblast needs to not lock you in a motion. Currently the airblast completely resets your velocity and makes you actually unable to move or jump (for scouts) for a short amount of time after the airblast. It should act like explosive knockback: surf-able, strafe-able, and slightly beveled so the pyro doesn't just get to look at a spot to make you go there, he has to understand his position vs yours and how the airblast will push you.
c. Engineer: the wrangler has potential. Remove the shielding and the fire rate increase given by the wrangler. The only benefit you now get is range. Also add a negative effect to the wrangler: dramatically (+100%?) longer time to switch weapons OFF the wrangler. If you get spammed you are pretty much fucked as you cant get your wrench out in time. You have to be smart about positioning and team support to make the wrangler work now.
5. Patch as many popular pub weapons as possible in a similar manner to the wrangler. Then these can actually be unbanned in 6v6 and HL to make comp more accessible.