Your probably right, but that would likely mean that destruction would be even more unbalanced than it already is.
Do you mean by making other high-level destruction spells obsolete?
I could see that being a problem, but there are ways around it, whether by implementing new uses/effects with their own advantages and weaknesses, or simply tweaking the existing spells to compensate (although that again sounds like more work than Beth would do). Even in the worst case, I would rather have a few spells become useless than an entire school of magic be reliant on exploits.
New Destruction spells? Like what? A straight up Damage Health spell? Can't think of much else we could really utilise.
Even upgraded versions of older spells like flames would be appreciated (say a blue flames spell that does more damage). Several entire spell effects simply lose their usefulness for high-level mages.