They did give us an ability that broke through immunity, it was this new SP, but it was a "bug" that they are now attempting to fix. Enfeebling is as I said, dead, and I doubt SE has any intent on bringing it back. They could fix RDM, Enfeebling is currently not a way to do it, especially not by making false promises about doing it later as they are currently trying to tell us. We have had an Enmity problem for some time, we have been told about Cait Sith/Atomos for 2 years, both of these are problems, that of which have not been solved because SE is slow with things. I am not prepared to let them give RDM an ability they tell me will be good later, when they can not even give me something that is good for my job now, and have been unable to do so since we were level 75 with the exception of 2 spells, Temper, and Refresh II, 1 of which is simply a 2nd tier to a previous ability.
Even if we could hit through immunity it would not matter much on most current events. And if right now is anything to go by, the future will be little different. We have content that is zerg or die, mobs hitting to hard to be able to survive, mob types that use TP attacks as standard attacks, which prevents Slow of Paralyze from taking effect even if they land. Enfeeblings problems go far past the fact mob are immune, there are a few that would be nice to land, like Grav for the -eva on some of the higher end mobs like Legion, or like the NM in Neo-Limbus which spams flash.
SCH was never meant to be the Enhancing job, it got stuck with it when Embrava came out because it got the best thing ever to happen to Enhancing Magic, and SE is now doing away with that exact thing. SCH is supposed to be an "over time" job now, Kaustra and Embrava are meant to be the extremes of both sides of "over time" magic, basically a super Bio and a super Regen. RDM had the highest Enhancing Magic skill from the start, and still does, infact though if any job beats us, its WHM. WHM has AoE spells where we do not, which often leaves us with the short end of the stick like with Gains & Bars. However if a job were to get a SP ability to enhance their Enhancing Magic I think most would agree the job would be RDM. RDM has more self buff spells than any other job, Temper, Gains, Phalanx, En-I, En-II, all of which would be effected, and would easily be balanced thanks to only effecting one person unlike Embrava which could fuel an Alliance.
I am not saying Enfeebling is not a roll of RDM, it is our highest skill, and something SE has tried to make it seem as if we are good at, but its just not effective right now, and RDM needs some more unique ones all to itself before its really worth even considering a SP ability dedicated to it. As it stands, any enfeeble a RDM can cast, so can a WHM or BLM, the only exception being Gravity which as we all know, anything relevant is 100% immune to. Enfeebling magic is in part screwed thanks to the fact SE is afraid of "Final Fantasy XI:Revenge of the RDM" from happening where we somehow DoT kite around VWNMs and Legion NMs to kill them within the 30 minute time limits.
I understand your view of RDM needing to return to Enfeebling as having a place for the job, but please look past that and see that right now, no content coming out can make real use of actual Enfeebling Magic. The only thing closely resembling that is Stun, and unless you made the same mistake as SE did in thinking Stun is Enfeebling Magic, you know that its Dark Magic and so it doesn't count either. Before Enfeebling Magic can matter again, they would have to redo alot of choices, a big part being redesigning how a few mob types work where half of our current enfeeblings, have no effect.