To summarize, so far 3 specific reasons were mentioned against removing older pickers for now:

1) Moultipass - that has to do with convenience of few buttons being upfront.
2)What, if I am thinking this right, Musocity meant, is for people to get used to it.
3) And by JJJ (which I also agree on)-leave it alone until the bugs are worked out then remove the unneeded dialogs.
----------------------------------------------------------------------
Best case scenario, if considered by PGM, this could be done in a few months until they iron out reported bugs with MTP Library. My realistic hope that it will be done in 2025 version, by the end of 2024.

I encourage anyone who will post / or cast a vote in this thread "against", please provide specific reasons why, even if they are repeats of the three mentioned above.
Thank you.