Right. So a Gravity Control/Thorns Dominator should have not been blocked by the switch to F2P.
Very few sets were actually blocked by that switch, and all of them were introduced with Going Rogue itself, if not later. The full list, across all ATs, is Dual Pistols, Kinetic Melee, Time Manipulation, Electric Control, Darkness Control, and Darkness Assault for the free ATs, plus Darkness Affinity and Demon Summoning for the ATs that themselves needed to be unlocked (Controllers and Masterminds, respectively).
So if Rayderoth couldn't play his Grav/Thorns Dom without a subscription after Going Rogue went live, it had nothing to do with those power sets or the AT.