What about third person shooter games?
Warframe has evolved into a really amazing MMO.
There's the ground game (run and gun)
The space game (gundam wing)
Content is solo - 4 man for normal content.
4-8 for raids.
Pvp is 8 ffa, 4v4 ctf/db
There's daily hard mode missions called sorties.
There's nightmare modes that drop rare mods.
There's vault modes that debuff you and drop rare mods.
Paying for stuff doesn't get you many advantages, everything is pretty much grindable.
In pvp, the top tier pve stuff tends to be worse than the starter gear (starter gear has higher DPR whereas end game has higher ROF, same net dps)