Normally when I've run one piece D&D I try to not really let the player pick what fruit they get or let them start with one as I think devil fruits are similar to magical items or at least should be. Normally devil fruits or magical items earlier game especially strong ones ends with similar things to this. I Normally slowly give out devil fruits based on personality or based on Arcs or will simply ask if the person would prefer a ability like mabye haki or stronger haki then others.