I think what GR missed out on was that it wasn't that viewers who bought into the optimistic Trek future wanted perfect humans, they wanted to relate to "better" humans who fought and successfully overcame their lesser natures on the show, not somewhere in the past or off-screen. Kirk wasn't perfect - he didn't always have confidence he was doing the right thing or have the answer right off, but he would find it.
Having Tasha have to fight to overcome her upbringing (or lack thereof) sometimes would have been better.
Yes, I think that would have been a great opportunity for everyone involved.
I remember liking the character when I first watched the series. I was sad to see her leave the series. However, now I find it tough to even watch Denise Crosby in the role...she is such a horrible actress...
To be fair, none of them did very well with the stilted dialogue and poor stories of the first season. I mean, look at Worf season one, and then season seven. Two totally different actors in a way. I think in time she would have found her footing.