I'd saying knocking off the lame-o SR restriction from Cone of Cold would go a long way to making it "1 level better". Cone of Cold does do potentially more damage (not at first, I'll grant you, but there's plenty of spells written with long-term payoff in mind) of a type that fewer creatures possess resistance to. Of course, the energy substitution feat might render the last point moot.
I guess you could go the other way around and slap the SR restriction on Blast of Flame and get the same conclusion, but I'm not a big fan of SR vs. energy damage.