I don't mind Luffy having mythical zoan. I mean we are in df world so I don't really care if he has this df.
And, from the beginning we knew he is special as he was the one who was destined to become PK. It became more apparent that he is destined when we started getting teased by "D". So, if his df ties him with destiny plot then I don't see any problem.
Real issue was how badly oda executed it.
Design wise it's cool.
Another issue is that constant laughing he does and goofs around which kind of takes tension away.
Despite being goofy all the time, these serious moments(like during fights) used to define him as the Captain....the determined leader.
Now, all I see is a clown bouncing around and laughing like a maniac.
I hope that it's side effect of Nika and oda pull some twist with this...