I think it depends on who you ask.

Developers I know typically like something simple, flat, and issue-focused. Think GH issues.

PMs tend to want more feature rich tools with advanced reporting and customizable views. Think salesforce.

Product owners (I haven't had many) just want to know "are we there yet?" and will rarely open any tool or learn how they work - they just badger the PM via email or in meetings.

My problem isn't that there aren't tools that I like, its that there aren't a lot of tools that can be "all things to all people."

If a tool was built on something simple (GH Issues) and added a layer of complexity on top for PMs I think you'd have a winner. Waffle (waffle.io) is going in that direction, though they aren't heavy in the PM tooling area yet(?)