I never had an ileostomy. I think this is partially a personal preference in regard to what a person considers tolerable. Especially at first, raw fruits and vegetables went straight through me. I did not consider this intolerance, since it did not make me feel ill or cause me pain. Some things still zip right through me, 19 years later, but I still eat them because I like them and I know they are good for me.
I guess since I had no expectations, I was not disappointed. I was happy not to be hemorrhaging from my butt.
Other people feel that that sort of function is intolerable and adjust their diet accordingly.
I would suggest that you try not to predict your outcome, good or bad, and assume things will get better with time and patience. Also, don't forget those half or more of j-pouchers who don't report here and are out forgetting abou their j-pouches.
Jan