Would you make sure that this time you would be in a guild that could raid?
I mean I was lucky and were in such a guild. But so many others weren't. Seeing as people were intimidated back then (they felt unworthy to raid and only some special very hardcore players could do it).
I'll let you in on a little secret: I never farmed Tubers. I never farmed all those potions/elixirs/scrolls/foods. I just had my manapots and healthpots. Maybe at times I had some elixirs. But overal nope. Too expensive and time consuming to make. Still while it was current me and my guildies took about 50% of Naxx and got near killing C'thun.
In our guild mostly only the tank had an Flask. The rest did not.
So in terms of farming consumables, you can scratch that unless you went for world first.
So again: would you this time grab your chance at vanilla raiding?
I would not with the knowledge I have today tho. Would be a bit boring to do it all over again. Especially since I know what it was like to buff the raid with a 5 minute buff per person etc.
I would this time make sure I had the best spellpower item+crit on my slots. As I had no clue really how to (for the time) play a paladin, I just went with whatever would look nice = lightforge armor. So I would actually crossdress this time and get the best perks (if there were any) on the crafting professions. I would have nice macroes and other addons.