I noticed in that BTL video that Scott was moving on stage a little more and active. I have a theory. Of course I think age, fitness, and time have effected Scott's onstage persona. Going back to the conversation about why he's not as active on stage anymore, I think it has to do mostly with aging and fitness. Back in the #4 era he was completely RIPPED and working out/running every day. I think hard drugs, too, gave him more energy performing. So being clean probably has an effect too (not that I know he's 100% clean, easily could not be).
Anyway, my theory is that, at least in part, his lack of energy onstage is related to the music he's playing. While STP is a great financial bonus for all those guys, those songs were all written 10-20 years ago. Most of the ones they're playing are in the latter part of that range. I think part of the problem is Scott, while still delivering awesome performances vocally, is just less inspired and "in the zone" singing Plush, Vasoline etc... I think we all saw on his solo tour that he was more active on stage, and I think the BTL clip was more along those lines. So while age, fitness, and narcotics play a part in the live changes, I'd argue that lack of fresh material was playing a part too. Good to see him more active and having fun up there. Lots to be excited about in STP land!