(Consider this my thoughts on a general text editor and not a review of Sandy - I've not tried Sandy since I found it on the Arch forums a ways back - long before being brought up here)
I've recently thought a lot about editors, as I'm not satisfied with vi/vim and emacs chains are shitty beyond belief. I honestly think a modeless editor (in the vein of a 'windows editor') but with sane home-row keybindings would be the best of both worlds - the efficiency of vi's hand placement paired with an ability to just edit text that I feel vi (and ilk) lack. Some very important commands (undo, cut, copy, paste, Save, Quit, Close) would not need to move much from the Windows world, but we'd need to come up with bindings for movement. I'd like ^j/^k/^l/^; for linewise movement and another modifier for pagewise movement - possibly ctrl +alt? but since ^j is return, we may not be able to do so without trouble. (we'd also need to devise some system for "go to end of line" and "Beginning of line") Honestly, I dislike 'modal text editors' as I feel they make the task at hand more difficult that it was to begin with. Sure there's a lot to be said for the power they bring, but with some forethought and planning I think that most of the power and all of the 'usefulness' of a modal editor to a modeless one.