Can we make a fixed width preview and scroll if height is bigger than window instead of resizing them? I find quite annoying when switching from one artwork to another in preview/prototype to have scale changes from page to page.
Thanks for the feedback! We've definitely are looking at a few approaches to scrolling in the preview window - both defining scrollable 'viewports', as well as the 'long artboard' approach. It sounds like you tend towards the long artboard approach.
Out of curiosity, were you building a web or mobile prototype?
FYI - I'd also recommend checking out the Adobe XD Uservoice forum, which is a great place to suggest new features. There's a similar feature that is suggested here.