C4 frustrates me excessively in matchmaking, especially objective. It's over powered because you don't need to use the clicker (I'm not even sure why you gave players a clicker). Just double tap X! Not only that, but you can replenish this super weapon with Scavenger
Flak jacket should help coupled with engineer to see it thrown. Other than that its not that bad. Oh I agree that I see it thrown like a basketball but its a game, its not meant to be anywhere near "real"
Headquarters spawn system
I think everyone complains about the spawns equally.
Joining games in progress
You can spectate and not join.
Spawn Trapping -
This goes back to your previous comment on spawns, they should be improved.
Headshots
When I got my AR's gold it felt like the more I tried the less I got them. Just keep shooting man.
Overall do not get frustrated with the game, dont let yourself be tricked thinking your an amazing player that deserves better. Just play, do your best and forget about the details or else your going to A) hate the game, B)Lose your mind thinking to much about a thing