We would love to be able to give the full ailment stack counts. We can’t do it without compromising the performance of the game. I know this seems like a trivial system. It’s something that people were very confused about why we didn’t have it at all for a long time. This has been on our feature request list for years. The 15 stack limit is the only way we have been able to get the performance we need to not cause major problems.
If we find a way to increase the visible stack count, we will.