Is it worth supporting OpenGL ES 1.1 and fixed pipelines when even the most low level hardware can support 2.0 and shading languages?
After all, every iOS device for the last 2 years supports 2.0.
You seem to be targetting specifically iOS. In that case, the question you need to ask yourself is whether you want to phase out users of devices older than 2 years old.
This will depend on a lot of factors pertaining to your targeted market, the nature of your app, etc., and only you can answer this question.
When you'll have this answer, then you'll have the answer to your question here.
Good luck, and may the force be with you :)