Surely this would mean a massive reduction in passenger numbers as not only is the 733 much smaller than a 757 it will be load restricted on some of the longer routes too, possibly as many as 100 less seats per flight available if the last 6 rows are dropped?
As for TCX321s they are obviously newer but that doesn't necessarily meaner nicer, and as I haven't been on one I can't comment on noise levels etc. but the LS cabins are nice enough so most passengers will be happy enough with their lot I suspect, and lets face it for a good number of pax price is the only thing that leads them to choose their airline.