You'd need to implement mob tagging, where once you hit a mob, nobody else can damage/debuff it. Otherwise you'd just have a bunch of people OOG slowing and nuking down mobs if the person ever got into danger.
Yeah this felt bad on Vaniki where you'd be in these odd level ranges with unlocked AA (via expansion) but no way to learn them due to levels. It could work if the levels were rethought but *shrug*. Having them all unlock immediately killed a lot of AA farming but was mostly replaced with loot farming.
I think a later start (tss?) but level locked with monthly or biweekly updates would be interesting. Classic through PoP is such a solved problem, that even shortening xpac time or messing with loot is just a bandaid. It would be fun to have a lot of content unlocked and relevant. There is so much that you skip because you already way outlevel it when the xpac normally drops. Having 12 xpacs worth of content unlocked but at level limit 40/50/60/etc would see new paths and item meta coming up. Part of the fun of vaniki and mischief was going to places you never would have gone to before because previously there was no incentive. Also digging through alla and trying to find OP quest rewards and drops for things you'd never even consider. Anything that can focus on getting you to do different shit than the classic -> pop treadmill would be great. Also, whatever rule they have to add to better incentivize grouping / raiding. Why the fuck are you playing EQ alone?
Question for people who played a lot of mischief, which was more impactful? The random loot or the free trade?