I've never played with an orchestra but I can only assume that the main difficulty of a concerto is the connection with the other musicians. I don't think Beethoven would put any technical problems in his concertos that are significantly harder/different than the ones in his sonatas. So forget about the technical difficulty and focus on the real problem of a concerto. Either way, I don't see the point of learning a concerto unless you have an orchestra that wants to play it with you.
Topic: Waldstein Sonata vs Beethoven Concertos