Return of Reckoning

I would propose the exact opposite as a solution.

It is already too bothersome and ill-advised to siege in the current state of RvR, where majority never want to do it either due to the heavy defense-biased mechanics, difficulty, lag or any other reason.

If anything I think it is fine to ...

problem of BW/sorc i see (as tank/ranged dps player)
-they self kill themselves while casting, so basically you help enemy team
-they go melee to make area damage, and being a class tough as wet paper does not help honestly
-guard cannot mitigate self inflicted damage (coherent but make guard ...