I think the current crop of new GT bikes have comparable weight to what else it out there.Totally agree with you that the GT setup is cool since it splits the difference in RC growth between FC and RC, it'd go a long way to solving the unpredictabilities associated with high pivots. However - if 650b is becoming mainstream, I'm not sure if the added complexity/weight from the GT system is still justifiable, since we can now have a given level of bump absorption with lower main pivot heights anyway. Unfortunately there's always a compromise between weight/complexity and ultimate performance on production bikes which is why things like i-drive, idlers, and floating brakes don't take off very well. Still, I like the idea - and as bikes get lighter, these old ideas could get back on the table.