I don't think this is about "finger strength". Your keyboard probably was very forgiving to an uneven touch and so your technique was that way ... which now is revealed.
Just go on playing, try different tempos, slow down if you have to. And, yes, doing scales will help you, but listen carefully to the sound while you're playing, or else they will do no good.
Use the recording features of your Clavinova, record yourself a lot and listen and analyze.