They've already come out and said they are not replacing Paula with Kara. If it's true, or not, I don't know - but they've made the statement.

I'm also confident they are talking about/showing Kara a lot in the beginning because she's not someone who is in the public eye a lot. She's everywhere behind the scenes, but she's not exactly a household name. They are probably just familiarizing America with her and it'll taper off down the road as we warm up to her being there.