Oh, I think they improved "gameplay" (in which I include ruleset, mechanics and UI, but exclude graphics, character customisation, etc) in more ways than you give them credit for. From what I can remember :
Patch 3 introduced the Party-Follows-On-Jump, so we don't need to select each party member and order them to jump (a massive improvement for the handful of players out there who play solo and with a party of 4 characters, instead of with a bunch of friends where everyone controls only one character).
Patch 4 (or 5, can't remember) introduced a shortcut (perhaps now even a button in Patch 7?) to Group All/Ungroup All.
Patch 5 introduced a new UI system for Ability Checks in conversation, so we can now buff the speaker without having to get ouf ot conversation, select Shadowheart, cast Guidance, and get back in conversation.
Patch 5 introduced a new food-for-rest system, which I heard really made the Long Rest not so easy to spam, and didn't introduce additional inventory management.
So, I'd say that we had a really fair share of major gameplay improvements that were not related to the DnD rules and Larian's homebrew.
I mean, I was referring strictly to core mechanics (rules of combat, the way skill work, etc, etc), not the occasional UI tweaks.
P.S. The long rest is as easy as ever to spam at will. The food requirement is there only as a pretense, but Icelyn is probably the only person on Earth which gets anxiety issues about it.
Especially given that there's so much food lying around at every goddamn corner that you could probably feed an entire starving continent for months even just with the stuff you'll find before setting foot in the Underdark.
