Covering ankles specifically for the duration of offering prayers
Regarding ‘the raising of shalwar for salaat’, certainly it's true that dragging garments like the Queen of England is arrogant. However, may I point out that people are in the habit of folding up their trousers for Namaaz, and when they are finished the trouser goes back down. Judging by the response to the original question, this habit makes no sense and should not be seen as a part of offering Salaat.
I absolutely agree with you. There is no dress specified for the prayers, except that it should be presentable. It doesn't make sense that one should try to look different while approaching formal prayers. If longer trousers are a symbol of arrogance, they should not be used at all, whether while praying or otherwise. Folding trousers for prayers makes no sense. I can understand the view of those who keep their garments above ankles all the time, although, as I have clarified, I have my reservations about the applicability of this requirement for our times. However, keeping ankles uncovered specifically for prayers is a religious innovation (bid'ah) which should be condemned.