To answer your questions:
Promo performances for FF: DISASTER
Tour: Still pretty stiff except the Hold It Against Me performance. The rest of boring, except she shows more energy in her face and looks like she wants to be there. That is an improvement to performing but... yeah
Rewind:
Circus Promo Performances: She started nervous at first, but then she did the performances quite a few times and finally got into it more and more each time. On GMA and X-Factor you see that she really put a lot of energy into it.
Circus Tour: She still put a lot of energy into songs. Especially Radar, Freakshow, and a whole bunch of other songs (especially compared to the FF tour). A lot of it is lazily choegraphed, but she moves faster and has way better energy. Except by the end of the show (Womanizer is last) she is tired. It's a shame because it could be a good performance, but they either have her doing too many songs since she clearly isn't the performer she used to be, or she needs to work out more.
It's a shame she is forcing herself to be a worse performer. It's like she is trying, but she isn't so she is getting worse. I have come to terms with it, but it's still sad to see her decrease each time.
There are good performances on the FF tour, but the Circus tour there was more youthful and faster movement to it if that makes sense.