If the full screen launcher is correctly designed, then opening a top bar instead does not speed up the workflow one bit: stop doing whatever I am doing, hit a special key combo, type in a partial name, press enter, wait for new application to show up.
A top bar just looks different and imo worse, as it doesn't underline enough what is really happening workflow-wise.
Now if you have a problem with slow or confusing mode-change animations, then the solution is simply to fix them so that they are understated, quick and not in the way of typing for your application. Ask any UX designer: modal is bad when it is not clear enough in which mode you are, how did you get there, how do you leave that mode. But if modality is needed - and a user has only one set of eyes and one brain - then it should be evidently shown.