That is likely to create a mess that could be even worse than the status quo.
The Overwatch developers have certainly set the bar very low as far as balancing is concerned. On the other hand, physically speaking altering heroes shouldn’t be too labor or time consuming of a process. I’m referring to application that integrates the actual changes for testing as opposed to including the animations as well. So I think there is a big difference between what Blizzard have done in the past and what is possible. I am a 100% layman but something tells me they have the tools to get things in there remarkably quickly. Actually, let me give you an example in Jeff Kaplan’s own words:
What they can do in the background for testing purposes should be doable at a much quicker pace, granted the ideas are there. The upcoming Experimental Card also provides an environment to involve players.