I think this is a great answer. Option 1: Compare old and new design with new users. Posting the designs in Mturk could get some unbiaised answers. Option 2:

I think this is a great answer. Option 1: Compare old and new design with new users. Posting the designs in Mturk could get some unbiaised answers. Option 2: Gradual design. Don't shock your users. Change things gradually. Thanks Chris!