For true strike,
If you play with tactical map and almost all (if not all) of the DMG options like I do, that spell is complete garbage. Facing, Flanking, Hero points and all the yaddi yadda are not prevalent in most games that I am aware of, but it is a fact that should not be ignore if we want to make an accurate evaluation of the spells. The way true strike works with these option makes it even lamer that it is without these options.
I am toying with two ideas.
Either make it use a bonus action or make it a reaction. You lose you chance to use shield, counter spells and many other good options like attacks of opportunities to give yourself advantage. At low level where reactive options are relatively few, it wouldn't hurt that much but at a higher level it becomes a relative tough choice (remember that we are playing with the flanking rule).