No, I would not assume that. I would design the game properly
Once again - and please listen - I would not have a difference between new players and veteran players in this way. Meaning, no "hard" mode raid. All raids would be extremely hard - and only the best players would be able to do them, but it wouldn't be about a gear ceiling - it would be a skill ceiling.
New players would have access to raids as soon as they reached the right level and spent a few hours getting some decent gear, in this case.
I would never make legendary items a requisite for any kind of content - it would be a luxury and they wouldn't necessarily be more powerful - just have more exotic procs and powers. You wouldn't see hundreds of people on the server with one - you would see 2 or 3.
But new players would have the same perspective as veteran players in terms of gaining access to them, by being good - not by having great gear.
You're locked down into this "WoW-mode" of thinking - as if there was no other way to design games.
The raid leader would pick the best player - and, once again, all players would have the same amount of procs on their weapons.
If you allow for 10 procs (which I wouldn't as that's overkill and a complete nightmare to balance) - then you must also allow new players a reasonable chance of getting them, either by generating the item with 10 procs built-in - or providing alternative ways to get procs.
I would likely just have 1 or 2 procs - and I would have "normal" magical items have procs as well, just less exotic.
Meaning, any normal magical item at max level that the new player would have - would deal EXACTLY the same base damage as a legendary item of the same type. The only difference is that the proc(s) would be different and less exotic or interesting on the normal item. Much like most Diablo clones work.
In my design - they won't be able to reset your procs. You keep them. Meaning all the hard work you've poured into getting items will NOT GO TO WASTE - because the only important part of them will be procs. Everything else will be shared among all items. Conclusively, procs become the most desirable power in the game - but they don't make them MORE powerful when they reset the rest of the gear. They'll just add more - and the vertical progression will be about non-proc gear levels.
But you wouldn't even need to increase gear levels - because the procs would still be the most desirable. It would be like Guild Wars 1 - where you kept expanding your card collection, but you could still only ever have 8 cards active at a time.
So, yes, my suggestion solves that problem with gear resets (even though gear resets wouldn't need to happen) - you're just not listening. You assume that having a legendary item in the first place is necessary to do raids.
That's your first mistake.
You also assume that legendary item procs would be extremely powerful, that's your second mistake.
They would simply be useful - like all procs should be useful.
Have you ever played Magic the Gathering? Think of Uncommon cards as normal item procs and Legendary item procs as Rare cards. Rare cards aren't necesarily more powerful or useful than Uncommon cards - they're usually more specialised and fits a specific purpose. Some of them you can only have 1 of in your deck - and my design is similar.
It doesn't matter if a veteran player is decked out in legendary items and a new player is not. They would be at the same ilvl - and deal the same amount of damage at the core level. It's just that the veteran player would have more toys and ways to customize his gear - meaning he would probably be better in certain very specific situations, but no raid would ever be about having the best items - it would be about playing your role well.
Again, it's like you want the design to be bad - like it is in WoW.
I'm explaining to you how it would work - and you keep going back to WoW - as if I was redesigning WoW
That's not what I'm suggesting.