A little bit of both, I guess.Garrett Wang is way more interesting and cool than Harry Kim. Maybe it's because by the time they filmed his stuff, he'd been honing his act on the convention circuit for a few years, but he's just way more engaging than his character ever was on the show. Does this mean he's a bad actor because he couldn't channel that charisma into his character, or just that they didn't give him anything good to work with?
I've meet Garrett in person and yes, he actually has way more personality than Harry ever did. Garrett off stage is almost as entertaining as Robert Picardo, except Garrett is also a big fanboy himself.

However, it's unknown if he's a Trekkie as well(like Tim Russ) or if it's only for the job.
In the acting dept., I don't think Garrett has enough experence as actor to grasp enough emotion to have made Harry more 3 dimentional. At the same time, very few Harry stories called upon him to be anything more than bland.
And I can definitely see that Kate Mulgrew had some issues with Jeri Ryan. The body language says it all. At one point when she's talking about her coming on the show, she does that little dismissive handwave thing. Very telling.
