Here's a potential tip/workaround:
If you want to use Designer for the main file and also have Publisher, create and style the text and text frame in Publisher then paste into Designer. You won't be able to edit the stroke/fill of the text frame but can edit and re-style the text, as well as resize the frame (ie anything that you would otherwise be able to edit in Designer). If you convert to curves then, yes, you can edit the stroke/fill but will have separate elements and non-editable text.
I've not tested this beyond the ability to do it, so if it's is dangerous practice (eg for print production) please post and I'll remove/amend.
I can see many reasons for editable text frame attributes being useful within Designer - yes there are workarounds (like grouping) but imagine creating a map with each map label a separate group of two elements... let alone any other styling or control you might want to add to differing instances. However, I also see that there is no bullet-proof logic for how you split up features for vector, raster and text manipulation applications that works for all use cases while keeping application complexity and interface workable.
Maybe one monolithic application IS the answer... but that sounds FAR too much like Adobe for my liking! 😉