Hey James,
Your design is cool, but i think the point about tactile feedback is not so much finding where the key is (with a dimple or so as you mention, btw silica gel?), but getting the feeling that you have pressed the key, the physical feedback of pressing.
I agree it might not be crucial for a phone, but for a computer, where you “proper type” long texts I think it might be tiresome.
Of course it’s speculation, would be nice to try, and i do appreciate that the design looks clean and futuristic. But in my opinion there will always be this divide between iphone and blackberry users, if you see what i mean.