Blaze without ice spear is the only practical way to get MULTIPLE knockdown hits. You can do that on one monster, but all the other monsters receive ~450 damage but with the 4 second cooldown, it'll probably take awhile to kill everything just by using 2+Blaze.
In comparison to melee/range, however, that's still pretty strong. Just about on par with Windmill damage, except it has an additional bang on your primary target. Compared to Smash/Magnum it shares the 20% splash damage, but with a much wider radius as well as ignoring protection for Crit.
My question was whether Magnum/Range spamming, with or without Frozen Blast and Barriers, would be able to match up with Windmill or Blaze. Just the fact that Blaze is nerfed by disallowing Ice Spear doesn't say anything about range being able to compete, only that Blaze is less awesome.
Even without criticals, it's questionable if range would be able to compete. We're also ruling out party/pet assistance (an allied Windmill can easily maximize Blaze) for the sake of Ranged.