I would say THF and DNC aren't quite "spamming" 25k Rudra's, they still rely on SA (1min recast) or CF (1:30 recast) respectively to deal 25k, also right now we're in the wkr event so more people are doing wkr = boss living less time.

What I'd suggest if lag + boss health being an issue, kill the other mobs, you get credit either way and it's probably easier to churn out damage on the other mobs anyway.