I don’t see the problem and why frost or sword rain would be needed to eliminate them. Just battled a few times against max elite arblasters and had no problem in defeating them. Could be that towers in those defences were not maxed.
Use elite paladins to support hero together with a few arblasters yourself and activate bladestorm when they are close plus hero scream. First arblasters die instantly and heal others, but only one time as was the case in my situation. Paladins take remaining ones out in a few seconds due to hero scream and even when the remaing troops are still healing they die. Troops don’t seem to heal a second time, looks like some cooldown time is active in healing process. I certainly don’t have max bladestorm yet, but combination with elite max paladins is very effective against them. So don’t run in front and try to solo, then you are in big trouble.
If you time the bladestorm right on time, even some barricades and fences go down with them. Only after they died, take out towers with sonic blast if they are still standing, because your troops probably did already destroy them due to hero scream. Since supporting troops grow, those towers make not a chance at all.
Just use heal to refill the remaing life points of arblasters, canons and paladins for next wave. That way double heal strength is used and hero isn’t slowed down at all.