i saw lvl 150+ players online this days playing with friends and helping noobs like me (still lvl 52) 
Grinding is boring? yeah, always is boring but if you want gear or lvl up…do it, you wont have infinite quest, maybe IMC can make dailies quests in a future
Extreme Lag: i don’t have extreme lag, maybe spikes but still playable
Weird decisions: dunno, i couldn’t play in the first beta, so, no comments
Bad Rates: like i said, i’m noob, i’m fine now leveling, i need wait for high lvl maps i think
Always Under Lvl: if you are higher lvl for that area, the game will be easy
No channels and alternative ways to gaining exp: in my limited experience, I believe that channels are generated when another channel fills, so is normal in high level maps there are not many channels or little-traveled maps. And Alternative ways to gaining EXP, i’ll said the same, dailies quest with exp cards rewards
Imbalance: dunno, i’m noob xD
an advice: if you want ragequit 99% of the time, get a break, trust me, it’s the best thing you can do