While I haven't had the privilege of playing GTA:O yet (and as I've scrolled down the page and read posts I don't I'll ever bother), I understand what you're saying and can sympathize greatly. Now, I used to play the online components of Halo, Battlefield, GTA IV, etc. a lot more than I do now because the communities for Xbox Live and PSN are absolutely dreadful.
Now, I realize that's like saying all PewDiePie fans are the same idiots who claim he's the only one who can play Slender or Amnesia or whatever, but it's truer here than anywhere else. I'm bad at most multiplayer games, and I admit that with zero shame. Truth be told, I wish I had been born early enough to experience the days of arcades, when skill was arguably a greater factor in success and if you had some choice words for who you were playing against THEY WERE RIGHT THERE.
Getting back to skill, however, a lack of it is no reason you should not be able to experience a game. I don't hate player progression systems, I just feel they could be implemented more...what's the word? Fairly? Better-er? As much as I hate it, Call of Duty is a series that I feel does it right. In any game, you're going to get XP (provided you don't quit out), whether you were a one-man army that slaughtered anything with the nerve to draw breath, or a camper hiding in the back of the map roasting marshmallows. None of the weapons or abilities (passive or active) you unlock via leveling up are miles above what you start with, and every gun/knife/dildo bat has it's ups and downs.
Like I said, I haven't gotten to try GTA:O, and while the MMO-style of what Rockstar is doing with it impresses me, the fact that someone on the team though it would be a good idea to award a player with a tank they can summon from the ether was a GOOD idea kinda makes me scratch my head. While it's a big map and you're not like to join a lobby with nothing but heavy armor operators, Rockstar should've looked to Trevor and thought "What would happen if we gave this guy a tank and dropped 'im into a city with a bunch of people armed only with handguns and rifles?"
Because that's what will happen when you give the racist, sexist, xenophobic assholes of Xbox Live a tank and drop them into a city with a bunch of people armed only with handguns and rifles, Rockstar. That's exactly what will happen.