I've been playing piano for about 10 years, and in that time I never really learned how to read sheet music. I have a very good ear, and usually just figure out pieces through listening to the recordings of the greats with little to no reference to sheet music. Technically, I believe I am where I'm supposed to be - the last two pieces I learned (successfully) were La Campanella and Ondine from Gaspard de la Nuit.
However, as I try to expand my repertoire into jazz and more dissonant harmony, my ear is failing me. I'm having to turn to the sheet music constantly, which slows things down a lot. So I'm setting out to learn to read sheet music. Of course, I know how the notes on the staff translate to notes on the piano - FACE and all that, but the most complex piece I can "fluently" read is something like heart and soul.
I see two options at this point - the first is to buy a bunch of those introductory books full of little, easy pieces to sight read and play through those. My fear with that is that I will bore myself to quitting piano. What I want to do is sit down with the Kapustin variations and just slog through it, sight reading it completely. I know it would be a slow process, but I think it would be a lot more fun and fulfilling.
My question is whether this is a viable method - is it detrimental to learn how to read sheet music with very complex pieces?