I like your ideas about improving pugchamp system very much.
The thing with me is I have 0 comp experience with 6s or Higlander(excluding 1 lobby that went horribly 'cos I didn't know how to play Medic) and I can't really tell what would the optimal system be based on experience-just logic and assumption.
What I can address is the in-game matchmaking system that is crucial for the wider audience(comp and casual).
Current casual servers are filled with a variety of people - friendlies, trolls, tryhards, fresh gibuses and people who want balanced matches(of course some of the groups overlap).
If Valve made several queues (and a good training mode explaining all the important stuff properly) to filter out the skill groups/ preferences it would appeal to more people.
1st queue: PUBS
Bring back the good old pubs. Mostly recommended for new players to learn the maps mechanics etc without the pressure of doing badly. Also more skilled players would troll around and experiment with different loadouts without their inner pressure of doing bad.(or is it just me?)
2nd queue: CASUAL
Pretty much the current Casual system, but that tries to pair players with similar skill level and focuses on the objective. Very close to the CS:GO casual- gaining xp but not impacting the comp mode. No weapon bans or class limits
3rd queue: COMPETITIVE
"Pure" comp matchmaking with an ELO ranking system and weapon bans/class limits and possibly several types(6s,HL, prolander, 4v4, ultiduo etc. -also available in casual for practice) for different preferences. It would serve as a genuine and reliable rank/evidence for the leagues and possibly implement them in its core.
I hope that this didn't go off-topic too far away (barely mentioned the pughchamp so waaay off-topic) as I feel this is a very important issue for the TF2 community and TF2 in general.
Best regarts,
-wannaBe
P. S. Keep up the good work with the vids <3