Picard didn't volunteer to be shoved into the Robot / Homonculus body, his ship mates decided that for him as a way to save his life. They deliberately put on some sort of safety limiters on his Homonculus body to not allow him to have any Android Level super powers which kinda suck.
If you're going to have your brain's memory engrams moved to a Biological Android (Bioroid) body, you should get some super human powers to go along with it, but sadly, they didn't want to give him any for obvious reasons (Patrick Stewart is old, can't risk him doing any action scenes), that's what you have the young folks on the set for =D