I never played MP that much - only with friends as far as I recall. But I've always thought that JA dumbed down that side too because of dual sabres and staves. Some veterans might say otherwise, but as far as I'm concerned I think that staves and duals turned the sabre gameplay in a button mashing contest.
So all in all, I can't say that MP in JA really felt like a leap from JO. Siege was neat though, too bad they didn't develop it more.
~Dark Cupcake of the Sith