There’s room for something of this nature, but I don’t think this particular idea works. Making certain things stronger would easily break the game without adding any more gameplay—you’d just have an expanded meta with everyone doing the thing they did before better. As a result, you’d have less variance in acceptable approaches because one role would do it so much better than anything else. Any implementation would also have to take into account that some roles will be more desireable than others.
That said, allow me to try to contribute something constructive too.
Rather than new skills and buffs to class mechanics, this system should focus on WvW specific things. Players should be able to choose a focus for each character and be able to reset it by paying a certain amount of some WvW resource (perhaps excess wexp points?). There should also be a cooldown between switching. The focus should not affect combat abilities as there’s no way to do this without being dragged into a whole new can of worms. Finally, there should be multiple viable options for each player.
I’ll try to create some examples, but it would be helpful if people could point out what sort of things could be affected. I’m sure I don’t know them all.
Crusader
+1% repair efficiency per 10 WvW ranks.
+1% starting build % on siege per 10 WvW ranks. Capped at 50%.
+1 supply per 100 WvW ranks delivered by Yaks you escort for at least 30s. Does not stack—uses highest bonus from all escorts.
Scout
+1% movement speed per 30 WvW ranks while in aura range of an allied structure. Stacks additively with haste and shrine buffs.
+1% capture rate for camps, shrines, ruins and outposts per 30 WvW ranks.
+1% siege damage versus structures on your BL or in your corner of EB per 30 WvW ranks.
Assassin
+1% movement speed per 30 WvW ranks while in aura range of an enemy holding. Stacks additively with haste and shrine buffs.
+1 point per enemy player or Yak killed per 300 WvW ranks.
+1% damage to enemy NPCs per 30 WvW ranks.
Marauder
+1 supply capacity per 10 people in your squad. Caps at 5, effectively.
+1% damage reduction from enemy siege per 50 WvW ranks. Caps at 70%. Stacks additively.
-1% falling damage per 20 WvW ranks. Caps at 50%. Stacks additively.
Vanguard
+1% chance per 50 WvW ranks to recover +5 supply when building siege. 30s cooldown. Caps at 50%.
+1 supply capacity per 200 WvW ranks for 30s after capturing a camp.
+1% damage to enemy siege per 30 WvW ranks.
Saboteur
+1% effect strength/duration to your traps (supply/stealth, not class abilities) per 5 WvW ranks.
+1% damage reduction per 100 WvW ranks for nearby allied NPCs (but not player summons). Stacks with other players but caps at 50% total.
+1% movespeed while in combat per 30 WvW ranks. Stacks additively.
-1% falling damage per 20 WvW ranks. Caps at 50%. Stacks additively.
Treasure Hunter
+1% Magic Find per 5 WvW ranks.
+1 item from Resource Nodes per 500 WvW ranks.
+10% Wexp.
