Any vague effort to improve that core functionality of segments: ways to reduce the incredible amount of overlap, ways to reduce the blatantly-incorrect records, all of that.
An ability to query my activities for things like "find me activities in Texas in 2010".
Really though, for me it's a lack of trust: their history is one of taking away features, breaking third party interactions, and ignoring issues. To be comfortable giving them money, I need to feel I can count on their service. Right now I don't. This guy sums it up very well:
https://medium.com/@cosmocatalano/on...k-b6928d6e8b5b