Wait. Now that you mention it, the bottom left part looks waaaaay too blurry compared to the rest of the signature.
I wanted it to look like it's the furthest part from the render so I blurred it a little, though it seems I went overboard at some point. Maybe I should rotate it a little too so it doesn't cover too much space.
I don't really like the look of the glass effect honestly, but it was the best image I could find on google. I guess it's time to search for some broken glass brushes.
Thanks for your feedback!