Perhaps make it like diminishing returns, at higher level you will received less stats compared to lower level, so new player can catch up easily until sweet point, and at higher level is merely a bonus.
I also favor diminishing returns but worrying at the same time if it discourages people to advance after certain point.
Progress is measured by how close you get to a goal (which may be infinitely far away but whatever)
Change the goal over time so newcomers will not be pursuing the same goal as the veterans.
This can be implemented as starting a new world every once in a while (or expanding the world and putting new players in the new regions), but you could come up with something that works in a single world/place. Like a new branch of magic to pursue that is slightly better than the old one when people start getting too good at the old one.
It might make the game remain interesting for longer for the older players too as they have to keep 'adapting'. Or it might just annoy them when their work becomes less and less worthy if they cling to it.
Pity adding a new world or something is not an option , but other than that your suggestion highly conforms to my plan of using "technology" but less cruel than you (starting over new stat)
Its ok if newcomer is 1 and veteran is 100 can catch sometime but when it comes to like 1 to 10.000 it is practically impossible.
Keep those players apart (don't make it possible for the extremely high-level players to kill novices).
My concerns are not only for PvP but also of aggregrated attack of a faction. Newcomers will lose interest at the point they see not only they can win but also can't contribute to the cause at all.