This will be controversial, but I'll start out by making following statement and premise:
Spvp is well balanced.
I truly believe the game is in an excellent state and there are only very small outliers that could be tweaked for some quality of life and a tad bit more build diversity. The only minor problem is Rev and this is only slightly over performing.
The real problem is player skill and population. Spvp has an extremely steep learning curve and there simply isn't enough space or time for the vast majority to git gud.
My suggestion is to create an ACTUAL division. Spvp needs an Easy-mode where new players can go to learn how to play free from smurfs and try hards. Easy-mode should be an arena setting that remains locked to the top players and it should be strictly protected by some sort of ruleset that ArensNet best determines keeps out the smurfs. There should be recommended meta build templates in Easy-mode and tutorials on rotations in the lobby. Finally, to draw players in, give Easy-mode some decent pve centric rewards that nobody in the top cares about, like the ascended shards and marks that can give legendary armor.