It will have unlimited FPS, but everything should continue to Diablo 2 Items run in the same tickrate and with the identical logic as the original game. If you enjoyed creating a hammerdin back in 2001, it seems as if you should be able to make the identical hammerdin in 2021.
Part of the allure of playing Diablo 2 online is the private and personal servers that may be made instantly, and keeping this feature around would serve the game well. Jumping into a series of Baal runs or even a trading area is core Diablo 2, and I'd hate to see it move. Ultimately, doing away with all the character expiration countdown which has claimed more level 99 Hammerdins than any hardcore playthrough is a great option by the developers.
This one does not need much of an excuse. Diablo 2 would not benefit from microtransactions, and being able to buy things with real money (looking in the d2jsp) would harm the in-game marketplace that may be quite fair and exciting. And adding makeup and pets actually wouldn't do much for the game that already has amazing artwork updated for the remaster.
A transmogrification system like in Diablo 3 are rather cool, allowing players to don different styles of apparel without actually changing equipment. Still, it would also change a good deal of the player experience. Experienced players may often tell exactly what a character is wearing only by outward appearance.
Adding in the ability to Cheap Diablo 2 Resurrected Items see another player's gear (as we have seen in a number of the greatest Diablo 2 mods) when clicking on them will probably be welcomed by a lot of people.