For me SL is quite good, not on the level of some past expansions, but still good.
What is required to enjoy it fully? I couldn't tell you. I enjoy questing, levelling, doing dungeons and raiding. I can do these activities and have fun, from LFR to heroic raiding (depending on the char I'm playing). I don't care about a lot of features in game, mind you: PvP, adventure table, pet battles to name a few, but what's left is good enough.
I always enjoyed the last months of an xpack because I had time to do everythinbg I wanted on several characters, SL is giving me a bit of this right now, so for my playing style it's perfectly fine.
The main question should be: why do you need to play wow every day for several hours?