She was great on Supernatural, so she should be a fantastic addition to TVD.
As for TVD itself, I'm enjoying this year just as much as last (last week's ep was excellent - especially the sheriff's realization/reaction). People actually complained that last year the show's plotting moved too fast, so perhaps any perceived slowness in comparison to last year is because they've decided to take things a bit slower this year. I don't know because I can't really say I've found things all that slow slow because in every ep there's at least one major revelation or significant scene that makes you sit back and go "Whoa" - and that's just fine with me.
so I think they may not have expected DS to go on past that.
Actually, they did have storyline plans past 1841PT (and were even negotiating Diana Millay's return as Laura). But getting into any of that would be going REALLY OT. Though getting sort of back on topic, apparently none of those plans included another touchy feely RD character.
Complete this phrase: Barnabas - "Excuse me, Mr. Shaw - but would you mind if I took a few moments of your time to talk about the delicate subject of...?!"
Complete this phrase: "While talking with Hallie, David hoped that she wouldn't notice that, with all the powers of concentration that he could muster, he was desperately fighting his right hand's desire to...!!"