I would say the biggest thing that bothers me is just having to wait till you're in the top tier before the game becomes social. I mean you can group on the way up and thats supposedly faster - but this game has little to no help in putting a group together. The grinding is tolerable in this game to me for some reason. I think it comes down to more accurately being the fact that I can wade into mobs that are all purple to me and, through careful play, I can farm them.
The player summoned bosses like Mog are a bit of a push over but supply some good rewards for you and your group. I think I could probably solo them, but it would take a minute. Theyre strategically easy to figure out. I havent had but one experience with a guild boss and that was with the Lava Chief in Lava Pit. But I was having a lot of trouble trying to figure out what was causing the stun that would inevitably lead to being one shot at one point or another. Staying on his back helped, but I knew I would die eventually. Not a fan of being able to run back to bosses in a zerg fashion, but if everything the boss does is random - I can understand it.
Im not entirely sure how I feel about the way weapons and armor are upgraded in this game, or how you get a more unique version - but I do like the fact that you essentially hold onto the same weapon or armor. I feel like when your gear is upgraded, that you're invested in it. It means something, unlike Random_Gear_01 thats tossed out every other level.
The world is huge, and I mean absolutely f'n HUGE! But even then, I can look across the map and know how an area looks across any part of the map. Im a completionist so a the leveling up game took me a lot longer than some people I know. The amity game that goes along with it could use a LOT of work, but the way you acquire knowledge on each mob, plant, NPC, area, sculpture etc. etc. is cool as shit to me. Why? I have no idea. But if something looks interesting to me, I can bet I can look into my knowledge tab and read about it. Places that you can visit just arent put there willy nilly in other words. Wizard Tower in the middle of no where? Look up what is said about it in locations and find out more in Theology.
I havent even really began to look into crafting all that much because Ive been so enveloped in the Amity / Knowledge part of the game and upgrading gear - but people speak volumes about it that have invested a huge chunk of their contribution into it. Ive got my cooking and things up but I have only hit the outer edge of what all the system truly has to offer.
TL;DR - I really enjoy the game. I wish some things were different, but anytime I get annoyed with how long something is taking.. when Im finally done or Ive accomplished what I was trying to do, I get happy as hell about it. No other MMO has been able to do that for me. Even when I slam my balls in the door to get a boss down and get a new shiny piece of loot in WoW, I dont feel accomplished. I feel relieved instead that its finally fucking over.