Well, I would say primarily the players lack of passing skills, and inability to effectively ISO.
I know you want me to say Igor - but I just don't agree with that. If for instance Ayton could catch the ball 14 ft out and be able to effectively make his way towards the basket ala Embid we could run the offense through him very effectively.
If we had a guard very good at penetration we could run effective pick and roll with them.
But look at our options - Ayton I already described
Josh jackson is a mediocre ball handler, and a lousy finisher. That doesn't work.
Mikal simply stinks at creating his own shot - that doesn't work.
Holmes is only able to finish within 6 feet of the basket - that doesn't work
Melton is not good at driving nor is he a good shooter or passer - that doesn't work
Okobo is streaky - but generally is also not a good shooter or passer or penetrator - that doesn't work
Crawford can get off a 15-20 foot shot consistently - but shoots it at a low percentage and is terrible at getting layups - that doesn't work
Oubre - not a good passer, not an efficient scorer, basically he is clean up the junk player ala a poor man's Ceballos - that doesn't work
Warren - he is able to ISO somewhat, and is in my opinion way underutilized. With that said he is a guy that kind of needs to have a running start. Just giving him the ball at the top of the key and expecting him to beat his man from there he is not particularly good at. Also his ability to pass is putrid, if he is shut down, you are looking at a turnover. But of all the options, he is our second best to Booker.
That is my impression - since you are so much smarter than Igor - please tell me how you would run the offense.