I'm a vet from all the games. If you can trust anyone you might be able to trust me on the situation. It isn't quite as bad as some make it out to be.
First of all the game runs better, is more balanced, and is just a better game than it was at launch. Clan support and retro maps are coming along with coop. Look to see a PS Plus deal at least this year I think for the MP portion possibly.
There are about 1000 online at any given time. This goes down during low peak periods. 1000 at a time is usually throughout the week. Right now there are about 1100 people on total.
The spawn rape is because, simply, people are not very good without autoaim and maneuvering through maps without it. A lot of noobs wander around in this game expecting vets to have spawns ready for them at all times. They are a pretty stupid breed of player and you can see this in their terribly low KDRs. Against some kind of irrational thought, you do need to have a decent KDR in teamgames because the less you kill the less you complete any objectives you set out to do. If you can keep around 1 KDR and do objectives you should be fine in this game.
It's not an easy game to just wander into. BUT the game is solid right now with the Insurgent pack. You NEED the M82 as a support and that gun should never have been behind paywall imo. All in all GG has done some pretty great things with performance. Where before I was dropping frames all over the place at random points, now the game seems somewhat stable in 24 player matches.
Honestly, if you are on the fence about this game just try it. The graphics are fantastic for an MP title. Best out there imo. At any rate in a few months the game will be even better. I must say the weapons in this game are imho the best out there PC or console.