Yup. She greatly overstayed her welcome. Not the actresses fault but the it was very clear the writers didn't know what they wanted to do with her and kept including her when it didn't make a damn bit of sense. I think it's season 8 where this is 100% clear if one had doubts before. Season starts off with her no where to be seen. Season is going really well and then when she shows up it takes a nose dive and that last until her small arc is over and she's finally gone and then the show is really good to great from that point on until the show finally ends with a dud here and there.
Seasons 4 to 7 are the worse parts of the series. There is just enough there that keeps or kept you watching though. Looking back thought seasons 1-3 and 8 (majority of it) to 10 are the best parts of the show. Must of the later seasons problems are more budget then anything else instead of actor, story, etc related if I'm remember correctly.
Yea, from 8 to 10 there was that one street they filmed all Metropolis outdoor scenes in, lol. Even the Clark versus Doomsday battle took place on that street.