I play classic consistently, so here is my opinion.
BEST for hell classic is Barb hands down by far.
Sorc is only good if you have max block and res, otherwise you can become toast when the mobs hit in A4.
Next up is Hammerdin, yeah kinda slow, but extreme tank with max block (holy shield) and res, you should be able to tank hits and cast and clear mobs using pots.
I play necro.... its SLOW, and unless you have the items, mana, and skillset to revive/curse/corpse explode fast, your minions will get crushed and you will be next.
Amazon....there is no way without a high damage gothic bow...Carrion Song was awesome for this back in the day.
Now I have never gotten to 99, highest I got was 90 and then I just couldn't do runs anymore, how long do you think it will take to get to 99? Best of luck and if you have any questions I'll help
Thank you so much for explaining everything. I think I'll stick with Paladin. I'll look into some builds. Maybe there's a Hammerdin + Smiter build, so I can quickly clear CS with hammers, and then use Smit to kill Diablo 8 players? Or maybe we can make a playable FoH Paladin, so I can quickly clear CS? I'll need to research all of this, but thanks for your help, I'll get to level 99!