hmm now i'm just throwing this out there, but i get the feeling that Kryptonite weakens the suit. Just something in the way they showed that scene with the Kryptonite in that clip and Lana said "If I touch that much Kryptonite" and Clark repsonded "You have to." It just doesn't seem like they can keep Lana in the suit for long because it goes against Superman and is just an excuse to keep apart Lois and Clark.
Oh and I agree with you dannixx I like Lana by herself as a character. Just the whole Clark and Lana thing is getting old, especially since we all know he ends up with Lois and they were so close! I miss the Lois/Clark sexual tension episodes! But as long as Lana is in the picture we know it won't happen