I do think it's a good point that what an actor is happy/sad with in a role is different than what a fan is. Actors, as others note, often relish acting against type.
OTOH, actors absolutely don't relish when their characters are sidelined and/or turned into the butt of jokes. Part of the reason why Robert Beltran was so unhappy on Voyager is he was under the impression that he'd be the costar since he was first officer, and then he was upstaged by The Doctor (and later, Seven). Hell, even Mulgrew was famously angry and petty with Jeri Ryan about being upstaged.
So, like, presuming that she didn't request it, maybe Jess Bush is unhappy that she's been given very little to work with this season? I don't think we'll know for quite some time, if ever.
What it comes down to to me is that you can do this sort of meta, postmodern romp through 20th century media on any show (it was done quite well by Community), but there's only one Star Trek.
Well, two Star Treks right now, but the point remains.
Let's be honest - aside from Picard, Data, and Worf, the TNG characters didn't have much character development, and can mostly be described by their role on the ship, relationships, and a handful of quirks.
Like, what characterizes Riker other than being a horndog? Or Geordi other than being completely hopeless with women? What characteristics does Bev have besides being a doctor and a mom? What the hell is Deanna's personality beyond liking chocolate?