I was in the same situation. I bought it immediately upon release.
It's definitely more accessible. At the moment the UI is overly mouse-centric with few keyboard shortcuts but this will likely improve. The UI is seriously shitty in places like the lack of sensible sorting of lists of creatures but it's not totally game-breaking.
There are some mandatory mods that improve the UI and icons, like some genius decided the "cancel squad order" and "disband squad" icons should look nearly the same. I don't need to list the mandatory mods: on the Steam Workshop just sort by "most subscribed" and subscribe to everything in the top 4 and check out the top 20 or so for mods that do things like add missing graphics.
DFHack is also essential of course, it fixes some annoyances like adding confirmation dialog for things like disbanding squads and adds a bunch of features.
I think that relative to when you stopped playing, taverns, guild halls, libraries and stuff should be new. They are good features.
There are some very glitchy and half complete things too, like the villains feature is only half complete, this is where there are schemes to steal your artifacts and stuff. You can interrogate residents and visitors and lock hem up in the dungeon, but it's only half complete. Of course there will still be bugs you are familiar with from playing a decade ago.
Necromancers can easily destroy your game by grinding it to a halt if you don't intervene with DFHack, they can be a source of entertainment but it's much safer to kill them on sight especially if you aren't willing to cheat with DFHack. Necromancers and vampires also can be removed from worldgen by changing some values.
Overall the overwhelmingly positive steam reviews do not lie. Most people are going to enjoy Dwarf Fortress premium and get value from money out of it. The main question would be whether to buy it now, or to wait longer. In favor of buying it now, mods and DFHack have already done many easy fixes, in favor of buying it later: there is still tons of stuff that needs to be patched by the devs so it should get better with time, though I wouldn't hold out for hope of the development pace not continuing to be relatively glacial, even with more devs working on the game.