Group fights are both good and bad.
Bad from two points:
- revenge with a proper build is retarded (damage really high), and you can do cheese knockdowns with the activation for guaranteed hits
- against players that know what they're doing you won't be able to win 1vX (as in they dont just spam attacks at you), revenge or not
Good from one point - it breaks the monotony of the ultradefensive playstyle that's currently how most tryhards play. Luckily there's not so many tryhards around yet (no ranked gamemode), but just because of that I like 4v4 or 2v2. It forces people to fight differently and can make for some interesting fights.
To sum it up, I like group fights myself.
As for P2P: sure there are some legit complaints but honestly more than 90% of my games don't have any issues (lags, disconnects). Seeing the comments in that video just makes me think none of those people have actually played the game or they don't know how to forward ports or something. They're talking as if the game is completely ruined by P2P when in fact most of the time players don't really have issues with connection.
Here's a funny fact, in Rainbow Six Siege, Ubisoft's other popular multiplayer game that works on a server basis, I have way more connection/lag issues (everyone does...)