WotC can relieve other parties of their obligations to it, including their obligations to offer OGC for sub-licensing.Although I said it's not nonsensical on its face, there does appear to be a logical contradiction. Per the licence, a publisher has to offer WoTC OGC on the same terms they received it, so they cannot both abide by their licence terms in OGL 1.0 and also not re-licence the WoTC OGC they received under the licence.
If I try to abide by WoTC's claim to withdraw their OGC from re-licencing, I am in breach of my own obligations under the OGL. I'm not allowed to amend the OGL to change the licence.
If 3PP X has contractual obligations to 3PP Y to offer OGC for (sub-)licensing, but (i) that OGC would infringe WotC's copyright but for a licence, and (ii) is not covered by permissions conferred by section 4 (as per my mooted interpretation), then X is in a quandry.
The possibility of inconsistent contractual obligations is one reason against the interpretation I've canvassed. I don't think it's fatal. Of course it would defeat the viral character of the OGL, but that's already a consequence of the canvassed interpretation.
I reiterate: I am not factoring in any interpretive implications of the FAQ, conduct undertaken by WotC and its officers, etc. I am engaged in purely textual interpretation.