The south american competitive scene is really small (there are like 27 registered teams in the new LBTF2 season), so small that everybody knows everybody in pugs. Even the best player at least heard about that guy in the pug server who doesn't know what is a ubercharge. But, three things have been impressing me with those stress tests:
1) I've been playing with a lot of guys who I've never seen before (most of the matches have been really, but really easy if you play with more people from comp in your team, but eventually this will be fixed with an ELO system)
2) There is no waiting time to find people to play, we just press search and it finds a match (and normally it is really hard to see 2 pugs going on at the same time in our scene)
And the most important
3) Most of the teams made of people who I've never seen before have been playing with a team configuration at least close to the default (and this seems to be becoming more normal in the recent tests). There is ALWAYS a medic, hardly full time spies and engies, some heavies but a lot less than Soldiers and Demomen. The only non-default class I've been seeing a lot is pyro.
It seems the pubbers are learning and they are really playing to win. This is giving me a lot of hope for the future of this game. If they keep gaining interest for the format, both pov streamers and match streams will become more popular, there will appear a lot of new teams joining the open divisions, the tf2isdead threads will stop.