I can't speak for the Wadia or the Aerials, but the Threshold gear is not bright. I have a T2 and it is the best line stage I ever owned. It replaced a Levinson 380S (that it totally crushed). Your problems are somewhere else in the system. The problem may be the listening room or your cables or any other number of things. I feel you would be making a mistake removing the T2 from your system.
PS. Most rock music is not recorded very well and that may be where some of the brightness is coming from.
PS. Most rock music is not recorded very well and that may be where some of the brightness is coming from.