Just my opinion but I'm a believer in there is no stacking, there is simply try and don't try.
I've been playing this game with a lot of the regulars for years. (Starting elsewhere then moving here.) Most days I know 90% of the players on the server. I've seen teams with really good players get rolled. It's usually because half the team decides a majority of classes being snipers; spies and scoots are great for accomplishing goals...yeah, OK.
When a team is getting rolled, look at the class page. I bet there is a whole lot of "Me-Fortess" going on. 4 snipers, 3 spies, 2+ scoots, 1 or no medics. And people wonder why they get rolled/don't accomplish anything.
I admit it, I "stack". I've always preferred red, same with a lot of the people I have been playing with for years. At this late stage of TF2's life, I play more for the people than the game. So of course I'll join a team with particular people on it. The ones that make it bearable. Seeing Valve, in my opinion, has "ruined" TF2. It's not the game I bought and loved years ago. (Yes, I paid for it, so I have a right to complain about Valve changing it from a FPS to a CFS....Cluster F*** Shooter!!!)
Ok, I know, from a business standpoint what Valve did was genius, but from a players perspective, too much BS added to this game. I don't find it fun. Especially on a 32 slot server.
As you say, there are some pretty damned skilled players on the server. Generally it's a good mix on both sides. It's just a case of if people are actually
trying or
screwing around.
I recall recently someone claimed we stacked red before the round even started. Blu wiped the floor with our corpses in short order....and we were the "stacked" team? I simply looked at the class board and it was all evident why. Yup, try vs don't try!