I looked at you album and you have definitely come a long way, front is looking really good! I agree the crown is a stubborn area to fill and is not known as the black hole of transplants for nothing. However, I think if you were to put another 1500 grafts in there you would be very close to getting the coverage you are after. Also bear in mind that your long hair probably makes your crown seem worse than it is.
On a related point, I do wonder if a lot of surgeons lack the skill to perform surgery on the crown in comparison to the hairline? You see some great coverage from Lorenzo on the crown, but not many other doctors spring to mind.
Everyone is obsessed with what doctors perform the best hairlines, but often little attention is paid to the doctors which perform the best crown work.....I'm sure it must be an art in itself, no?