The Ranger genuinely needed a rework (and I think at the very least a level 1 Ranger no longer feels remotely like a poor man's level 1 Fighter), and there are a few other changes I think actually addressed problems or seem to serve some sort of discernible purpose (I'm not sure I like the new two weapon fighting, but it's attacking a needlessly complex system so I'm glad to see them working on it). But to me mostly this seems like a lot of change for change's sake.
That doesn't make the changes terrible per se (although I think spells prepared being tied to spell level, and making memorized casters prepared, spellcasters are genuinely terrible changes). But my overall impression is that this all seems pretty aimless and pointless. If this is all OneD&D is going to be, than it really is nothing but a refresh to force me to buy new core books.
If they seemed to be going through everything with a few clear (preferably stated) goals in mind, whether they were simplification, or addressing common complaints, or even something I have no interest in like fixing the CR system I would have a lot more respect for the process even if I didn't like or agree with all the changes. But at this point I think goal one for the bulk of changes (if not for the most important ones) is to change things just enough that you can't use your old 5e PHB in a 5.5e game.