Very often, as people - and especially as minimalists - we tend to search for the best all-round tool. I think exploring extremes is a better strategy.
When it comes to productivity tools - you can not find one that will fit your all expectations, but you can find two - that could be all you need.
I can not have one software for my productivity - I use two, Asana - for my project management, and a Calendar- to plan effectively my day.
I think you should have extreme tools to manage your productivity. Something very specialized and simple - like a Calendar. And also something more complicated and flexible to accommodate any workflow - like Asana.