Honestly after getting used to the Odyssey UI for the past nine months, I have grown to prefer it. Especially because it lacks that stupid, persistent, irremovable popup menu that appears whenever you hover over anything in the maps in Horizons which annoyed me to no end. It's not without its issues (the occasional bugs and lack of back button support in some screens are also very annoying), but I'd choose it any day over Horizon's UI.
I think at least in part, the Odd UI was revised to address this common complaint about the pre-Odd UI. However ime that pop-up that can obscure part of the galaxy/system display has been replaced by large pop-up panels that obscure great swathes of the display, and instead of requiring small precise controller (mouse in my case) movements to hit each button, require large but still precise movements.
So I agree that the old UI had that issue, but imo the solution in practice is a worse user experience, but for different reasons. The finickity selection process still persists too, but now instead of only having to hover in the right place I often have to click 5-6 times to get the new pop-up to pop up.
My regular gripe in-game (I have only played Odyssey for at least 6 months and have used it a lot) is the ship UI and less regularly the module storage UI. I regularly want to switch ships and have to scroll down a list of them that I cannot sort by ship type, distance, cost to transfer etc as could easily be done in the pre-Odd ship UI. With the stored modules I seemingly have no way to check by location other than to go through every category & check manually.
I have mitigated both issues by storing every ship I regularly use (and all modules) in one location (currently on my carrier). It is frustrating that the new UI lacks these basic management features the old one had - the simple ability to sort a list. The new ship UI is also pretty sluggish, taking over a second to display the (pretty) ship with it's correct cosmetics applied, but the full colour images of the ships in both lists only display a default image for each ship type & not the cosmetics applied. The old line drawing ship UI was fast & responsive, and at least hid the lack of cosmetics behind a 'sci-fi' UI consistent with the ship's HuD.