I think this is a good idea for a LLM wrapper app.

I've heard the leaders of the foundational models say a similar thing: bet on the technology getting better. That is, if your business idea becomes less valuable given a smarter model then it isn't a good business idea. Alternatively, if your business idea becomes more valuable given a smarter model then it is a good business idea. (Not that I totally trust them, but this does seem like good advice)

So, even if your current product has some issues now with the diff provided by current models - consider that it will only get better as the models get better.

You are going to see a lot of competition in this space.