The gear you get, the marks, the faction rep all pales in comparison to PvE. Crucible: No reliable end game loot, completely at the mercy of RNG, and only 2-3 marks per 12 minute game. No transparent skill based matchmaking throwing veterans in with newbies. Smaller map sizes leads to homogenized weapon loadouts. Lackluster selection of vehicles to use. Semi available Iron Banner with the ability for two pieces of end game armor, requires reputation grind, which does not carry over from previous iron banner. Now compared to PvE. Strikes Range from 2-6 marks for each completion based on level, and with a good speed focused team you can complete most strikes within 10-15 minutes. Also guaranteed engrams and rep as well. Weekly heroic 400 rep, 9 coins, engrams Nightfall 500 rep, good chance at high level gear, Xp/rep boost for the week. Finally raid normal/hard End game loot, pure and simple. Patrols Mats, rep, and xp. Public events as well. So with a finite amount of time, and this game being structured to be all about that shiny loot, focusing your efforts on PvP has a high cost in time with a low reward in loot. I don't think bungie is unaware of this fact, and is why most if their patches are focusing on pvp, because if pvp is even a little unbalanced; it will be abandoned very quickly.