I think it was a wise decision. As far as sound signatures go, I think the HD650's suits me better. The AKGs were just too frail and thin. They did shine at times with certain genres and songs, but more often than not, I was left fatigued and wondering why they sounded lousy. I tried EQing them, tried numerous amps/DACs, and nothing really ended up perfect (for my ears). Just the way the K702 sound signature is, I guess.
Well, now I am running the HD650 from the Ibasso D6, and jumping between genres, and everything sounds good. Detailed, spacious, full-bodied... I like their sound signature.
IMO, it is good to have a more "universal" open headphone. God knows, I don't need to own 15 different pairs.
The HD650s are indeed more mellow, and less tiring than the K702s. I like that. More treble for me, doesn't mean more Hi-Fi; it means more tiring/less headtime.
Going to keep listening.