I too wish an updated DRZ or bigger WRR would hit the market and the lack of that is part of the reason i dont have a replacement bike yet.
ADV Grifter raises some good points.....some more time working on aggressive offoad speeds will make ADV pace riding seem easy and hopefully avoid the need to pick up the bike as often. Then, get in the weight room and do some dead lifts. Then you will have no problems riding any of the porky 650s offroad, and still have a bike that is ok on the interstate.
I started on a 650, but turned the dial back a bit and spent some time ripping around on 250s and a 400. After a while I found I could handle the weight of the 650 better just from body English and better line choice, throttle/clutch use etc., and tended to choose the 650 more due to its comfort on the way to and from the dirt. I am in no hurry offroad so poking along in 1st a d 2nd gear on a 650 is fine....but I do avoid any sort of technical hills though because of the weight thing.
The Sertao, Terra, 690R, and DR650 are all in the running...it will just depend on price and availability when I get a chance to get back at it.
'12 Sertao, '12 Tenere, '04 Tiger, '09 WRR, '06 DRZ, '06 TW, '01 250 EXC, '09 KLR