A couple of things would make TP a lot more enjoyable:
1) When viewing an image (after clicking on a thumbnail), I should be able to show the next or previous image by using the right-, left-arrow on my keyboard (which doesn't seem to have any effect.) Currently I have to find the right/left arrows in the image nav bar - and the position of the these change as the image size changes. So I have to hunt for these with my mouse every time. I simple right/left-arrow on my keyboard would make things a LOT easier.
2) When changing to 100% view on an image, viewing the next image currently reduces that new image to the default screen fit. I would like to keep the 100% view on all images, and use my mouse wheel or my up/down keys to move up/down an image that is windowed at 100%. (The mouse wheel is now used for zooming in/out, which is probably better used for image navigation than zooming.) Having to click a zoom in/out icon would allow the wheel to be reserved for image navigation.
3) I should wish to have a command to locate and highlight all folders withing a tree that contain images which have not yet been thumbnailed - without having to do a complete rescan of all the images in a tree (takes too long that way.) And a rescan, although it will color folders appropriately, may not show me a buried folder that needs to be thumbnailed.