The Pel armour 4-piece bonus has become immensely more powerful now that Aim can be used every 20 seconds if fully traited. I can't imagine why anyone with access to four pieces wouldn't use them for red builds (or blue builds that go deep enough into red to fully trait Aim).
Your question was about raids, though.
In Throne T1, I don't find yellow line useful outside of the boss fights. The gauntlets between bosses are zergs, so no need for yellow line's higher single-target dps marks (Reveal Weakness / Snag / Enrage), debuffing tricks, or Riddle-locks. Also, with champs blowing their horns and LMs flinging stuns/mezzes around, Riddle is easily overriden. If you really want to use cc in the gauntlets, go blue and Provoke+Gambler's Strike to immobilize something. I do that to lock down trolls, for example.
I am hoping that gauntlets on T2 will require more cc mechanics; but even if so, Provoke+Gambler's Strike will likely be better than Riddle, since it can be applied to more targets, lasts longer, and (with proper attention) can be sustained even when the mob is being dps'd. Of course, even in blue, you can still Riddle; you just don't have the shorter cooldown.
Vikky (115 LM) * Iaggo (115 Burg) * Samsgarde (115 Captain) * Samsgaard (85 Guard, retired) * and others