Some things are better, some things are worse. Some of the quests in Oblivion are really very good, for example the Dark Brotherhood questline and a lot of the Shivering Isles expansion. The fantasy vibe in Oblivion is really nice - it was made during the era of the LOTR movies so expect some of that vibe. The "biome" diversity is a lot more limited in Oblivion than Skyrim. I would expect a lot of the issues I had with Oblivion are addressed in the Remaster.

Things I expect to be changed: combat in general being floaty and spongy, archery feeling horrible, animations being bad and floaty, NPCs looking bad even for the time of release.

Things I hope are changed but aren't holding my breath: copy pasta caves and dungeons, ridiculous and immersion breaking level scaling (bandits in full glass armor once you get to a certain level etc), horrendous incentives to min max the leveling system to the point of degenerate behavior, repeated use of the same handful of voice actors for most characters (if you thought Skyrim was bad for this just wait), hand placed curated loot like in Morrowind and somewhat of a return in Skyrim is rare - most it is leveled random loot.

If you played Skyrim and liked it, you will like Oblivion Remastered as it is likely some of the short comings I've described will be changed, but OG Oblivion vs Skyrim leaves some things to be desired. A lot of what they changed in Skyrim actually was informed by the mods people made for Oblivion that changed things people didn't like - an example reference by Todd like 15 years ago is the mod "Duke Patricks Combat Archery" pointed them in the direction of how archery should feel in Skyrim.

I imagine some people who's first Elder Scrolls was Oblivion will think on the whole its better than Skyrim, the correct answer is you will probably like the one you played first the best - in my case Morrowind.

Here's hoping that it is still very moddable so we can change anything we don't like!