Well, James does seem to be getting less meaner, I mean, before he would do all sorts of bad stuffm and even his Pokemon looked scary, with an exception of Victreebel and Weezong, but, when these two Pokemon were gone, James started to get cute-and-not-so-mean-looking pokemon, Cacnea, Chimecho and now, Manene.
Also, I doubt Manene will evolve, just like Cacnea, because, like mentioned above, I think the writers are trying to give James cute pokemon instead of scary and tough looking ones (these kinds of Pokemon are what Jessie usually has, even though, she would want a cute pokemon herself) but, if Manene does evolve, then, well...I dunno.