By the way, I heard a CD of, "supposedly" Ravel playing Ravel. I'm not 100% sure of its legitimacy, but if it was correct, I'd have to say Ravel is the only pianist who has played his Toccata to my exact demands, and to know that Ravel plays it exactly how I want it to be played pleases me.
About composers playing their own works, it reminds me a recent interview of Hélène Grimaud who, talking about Rachmaninoff playing his sonta N°2, had this interesting point of view that the composers are not as respectful for their own works as anyone else would be so their own interpretations are not so reliable as to building an opinion on how a piece should be played.
perhaps, did he have some difficulties to play in his late years because of his ilness ?
Actually, that is a misconception. Ravel was a rather accomplished pianist, and even considered becoming a pianist or a composer. Luckily he chose the latter. But the truth is, he played pieces like Chopin's 4th Ballade, and with a great deal of musicality, too! He won a piano performance competition at the conservatory.
Please note:Tempo markings throughout this score are not suggestions but indications of absolute speed. Rubato should only be employed when directed, and then only sparingly. Romantic interpretation of melodies, phrases and gestures should be avoided wherever possible.