That just gives you an excuse to play through again...
I'm in a similar position. I want to dump Aerie for Anomen (who I've never played)...but I'm in the romance. I want to dump Jaheira for Vic, but I want to see the new Druid abilities. I dropped Minsc for Saverok...good riddance. I want to dump Nalia for Edwin, but I've got an awful lot invested in her.
I'd also like to drop Imoen for another fighter or Jan, but I think that she's going to be a larger part of the plotline very soon...
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Now where did I leave that doughnut?!