On the 5v5 point, rip scout mains. I assume and still think that there are generally more scout/soldier players in the community. In a way this could also be bad for now if a scout would be the class that would be cut, that scout would require a whole new different team that requires 2 sollies, 1 demo, 1 med...aka you have to find another med player and assuming that there are decently low amount of med players. It's like how people want Highlander for 9v9 in MatchMaking, for every one pyro that wants to play a HL MM match, that requires 2 medics, 2 heavies, and 2 engineers(one for each team and assuming that those are the least played/picked). On the actually gameplay basis of 5v5, that makes scout a bit more vulnerable as scout combos are strong together and can be very tough to play alone time to time. There will be even less variety and the scout's role may get worse.
As for respawn times, you are suggesting that we slow down the game and make things longer in order to help make it an eSport. This only works for games such as Dota 2 and LoL, essentially MOBAs because they have a more defined early, mid, and late game. SC2 is changing to a faster paced game with it's 12 workers in the beginning and need for early expansions, which allows for more variety of builds and combos. But FPSes are a different story. TF2 is somewhat of a fast-paced FPS game if not the fastest team based FPS game that is still alive today(sorry quake i love you). The way soldiers, scouts, and demos play is somewhat fast and each kill is important. If you make respawn times longer, then dying would be HORRIBLE. You have to remember and note that killing in an FPS is generally fast and happens more frequently than it does in a MOBA. The respawn times in games are set to a decent scale depending on the speed of their games. While TF2 respawn is a bit weird and works in different ways of cap points and such(check the wiki), it has somewhat done us well. Changing ubercharge times and cap times longer is a bit too much, as it's changing one of the bases of the game pretty harshly. There also seems to be no problem with it either as far as these past few years have been.
Overall, you have stated that you wanted to broaden it to a larger audience. But if the only way to broaden it is to change what we are used to, love, and what the game really is, then it's too far. It's important to not change the game too much in what the community loves cause it's also what we liked in the first place to keep staying all this time. It's like how the Melee community loves how things are in Melee and they stayed with it. I think it's a popular choice for the game to stay the way the people who are loyal and already play it rather than changing just so other people can start to like it.