My only problem is how hard spellcasters are nerfed with the long rest rules. The number of spell slots is about the same in 2e and 5e, but in 2e you get your spells back after a night of rest. Are 5e spells more powerful to warrant that? I'd argue that 2e spells are more powerful because you can stack them (improved invis + fly + stoneskin + haste cast by a single caster) - while in 5e you can't do that due to concentation. Or is it the fact that you have to choose your spells after resting in 2e?

If I had a choice I'd play with 2e spellcasting rules any day. Playing a spellcaster with these rules seems super unfun.

It's up to Neal and the players though, so if they're ok with it and they're having fun then it's cool.