Yeah, the Glock has the disadvantage of a single action with none of the advantages. As far as your finger is concerned, it's a single action, but it doesn't have the nice, tight pull of a single action. That doesn't bother me, and I carry and compete with one, but it's definitely a hybrid in terms of its internal operation.
The "Safe-Action" of the Glock really just prevents the gun from going off unless the trigger is pulled. You can drop it or do anything else to it and it won't fire because the striker isn't completely cocked until the trigger is pulled that last little bit.
Fortunately, "second strike" capability isn't really part of anyone's competitive or defensive regimen. How many schools suggest a second pull on the trigger if the first one doesn't do its thing? I wouldn't even consider it. If the gun doesn't fire when I pull the trigger, an immediate tap-rack is what I do. Wasting time pulling the trigger again is just a way to get your times further up there. And, the trigger on the Glock, even though it doesn't feel like a single action, has a pretty short reset and can be made light enough. Works for me!