Having talked to multiple medical professionals and people involved in research, the techniques now probably will not change much if at all. Phalloplasty is quickly overtaking if it hasn't already overtaken metoidioplasty in terms of popularity. If there are developments at all in the future, it will mostly come in the form of better erectile devices, which currently have a very high complication rate.
I personally put off transitioning because at the time bottom surgery didn't seem that impressive to me (2006). There has been enough improvement in that time that I've come out, completely transitioned, and am planning on surgery. I think the procedures as they exist now, when performed by the best surgeons, will be about everything we could ever hope for.
If you're waiting for lab grown penises like I've heard some guys want, I know nothing about it. I imagine we would be the last in line to get them if they worked out.