note: yes I know people love the 20 man format, but humor me.
Just for kicks
imagine 10 man was back. (as in you can do highest difficulty raid as 10)
imagine all previous raids were made available via timewalking.
ok guys. fancy going back to black temple? how about Ulduar? No lets head to ICC!
all raids drop loot appropriate for your spec with ilvl that is current when out of timewalking.
and also, I would:
1- bring back reforging
2 - remove titanforge procs , remove artifact weapons
3 - remove legendaries as RNG drop and
4 - add 1 legendary quest: complete all timewalking raids
5 - two raids difficulty: normal / heroic and last bosses real hard