The first part is fair enough, now for the question, I don't know what 'good enough' is. Good enough for us at the moment? Good enough if we want to win CL, EPL, triple crown, whatever? No idea. You're as good as you play I guess, all I know at the moment that he pretty much is our player and it's not going to change until atleast January (and I doubt he'll be sold then anyway) and he's been our most consistent player. I also do know that he's pretty much one of very few players we have at the moment who trully can be branded as United quality as far as his mentality and character is concerned.
Before you jump with your 'elbows' and all that funny stuff, please do remember that this guy was booed by his own fan, not once did he throw his shit out of the pram but he's done all he could under LVG and Mourinho to prove his worth and it takes a real man not to crack under such pressure and turn it around 180. Sometimes you have players with far superior techique and ability compared to him who simply fail to cut it here due to their fragile mentality, character, you call it. Look at ADM. Sure, just character or right mentality won't take you everywhere but I do believe that there is a place in our team and probably as the time goes in squad for him due to that mentality alone. He's not a hinderance in our squad, don't think he ever was ever since that disastrous Moyes season.
And no, I don't think that defining our upcoming season as 'poor' just purely because Fellaini is playing well is fair. It's pretty silly, again.