I dont think there is much money in arrangers on ios.. considering the amount of work it takes to rewrite for ios. (apple has a very specific design platform) and all the features Dan plans to add to Varranger on PC... i can understand why he is staying away from IoS..

I think Dan has come to a point in development however, where he needs to find new sources of money... thats something we have seen with the addition of the brand specific soundsets..
I guess most people really interested in VArranger allready own it, so either he needs to find a reason for those people to spend more money on Varranger, or he needs to add something that will make new people buy it..

But IoS at the current IoS prices and the very specific group of people interested in a product like this does not seem the most likely road.