Deselect selections..? cmd/ctrl+d ? There is plenty of good key commands in Manga Studio as well.
I've read a book by Steve Krug so I can say that neither Photoshop CC or Manga Studio 5 has interface that doesn't make the user think. They are way too versatile programs to have everything in with in thinking distance of your second click.
But I can relate that you don't want to learn a new program, though I still find it bit unfair to say that it makes a program bad.
The interface can be customised fairly far as in many programs these days.
Also Manga Studio has very quick manipulation tools, if you mean resizing a sketch or such, just M to get your last used marque tool, or select from the now visible menu your favoured type of marque and make a selection. After that a bar shows up with options to: deselect (I use keycommand: cmd/ctrl+d), inverse selection (keycommand: shift+cmd/ctrl+i), expand selected area, shrink selected area, clear (the area), Clear outside selection, scale up/down/rotate (free transform the area, for the layer keycommand shift+cmd/cntrl +t), Fill (set main drawing colour as flat colour to the selected area), new tone (create raster tone for the selected area) , and lastly but least you have the button for settings(!!) to include or exclude other options to this...
You might have given up too soon 