The build time estimate flashes by quickly when the g-code is prepared, and isn't available and doesn't appear again until starting the build. Can this be added as a menu item or added to the Preview display?
Even better: In the preview, have hh:mm displays that track the sliders, showing time (after start of build) for the each slider's position. As you slide each slider to show the "start" and "end", you'd see the times associated with the slider position updated along with. (Isn't that a basic Windows / GUI guideline ref. Johnson, "GUI Bloopers"? A slider should have an associated numeric display to show the actual setting, shouldn't it?)
For that matter, could the preview display come up with the upper slider fully left and the lower slider fully right, showing the entire part? Having preview come up with nothing but the build platform shown, the first time I ran Creator, was a little "disconcerting"! Now I know what to do to see the part. Would be nicer to just see it, then tweak the sliders as needed for details of particular layers/sections.