Hello,
The single most important show stopper for myself and my teams to be using Planner (or whatever it was called at any given date) was the inability to save the current view as default. If you have to - each time you go to your Planner tab in Teams or the corresponding web version - recommence setting your required filters - you actually simply stop using the tool after Day 2. We found it utterly unusable.
So I would kindly like to ask you to ensure this works in the new version. It could be a simple solution like in Microsoft Lists: Here, you can create a "view" that saves filters, displayed fields etc and as these are added as a URL parameter, you can easily bookmark different views of the same list.
In addition, if you promise that finally, users will be able to see their tasks in one place - please delivery on this promise by including tasks from multiple accounts. The new MS Teams experience already improved the ability to work with different accounts - though the user still needs to manually switch back and forth. Truly being able to see tasks (even those assigned to me in other accounts where I am an "external" user) in my main account would transform the way I work.