Even WotC doesn't claim - as far as I know - to be able to destroy the existing ecosystem in respect of OGC that does not reproduce or derive from WotC's OGC and hence doesn't depend, for avoidance of infringement, on a licence from WotC.
I mention this mostly because I've read multiple posts on some of these threads that seem to think the opposite.
I agree they don't claim it directly. They are however making claims that put together with the text of 1.2 have an uncomfortable level of implication.
1) They claim they are deauthorizing 1.0a. They do not specifically state "instances of 1.0a between us and you", but 1.0a as a whole. Their implication, despite me understanding they have no actual power to do so, is that nobody can form any further 1.0a agreements between themselves.
2) 1.2 is unsuitable for use as a drop-in for 1.0a if you are licensing multiple works from multiple sources outside of WotC. It does not contain the mechanisms for that unless you are able to use the 1.2 between you and WotC alongside the 1.0a between you and a 3PP. The very text of 1.2 cannot be used to form a workable license where WotC is not the licensor, and we do not have appear to have permission to modify 1.2 in the way we can with 1.0a's Section 15, nor to even change the preamble stating the license is between WotC and $party. 1.2 also does not confer any offer from us to the downstream reader, nor does it grant any sublicensing ability whatsoever. Nor does it provide for identification of Open Game Content and Product Identity.
3) If 1.0a is deauthorized between $3PP and ourselves, we therefore need to fall back on the clause in 1.0a allowing the use of any authorized license, but as mentioned in 2) we can't use 1.2 for that purpose without making an extra copy of it and modifying that heavily, which we have not been granted permission to do and which would turn it into a version that is no longer authorized.
Now, my view here is that if I want to use 1.2 alongside some Open Game Content by Paizo, and license my own work onwards I need to do the following:
a) have a 1.2 agreement between WotC and myself for the SRD
b) have a seperate 1.0a agreement between Paizo and myself for the Paizo OGC.
c) either include my OGC contribution in b) or add a
third license to the mix to allow readers to license my part.
While I am confident WotC can legally do nothing about the inclusion of b), in their own words that license is deauthorized. I need to hear clearly from them that they only mean for OGL licenses where they are the licensor, and not those where other parties are the licensor. Currently they seem to be ignoring any request whatsoever for clarification on this, despite it being likely to be the
biggest concern of most 3PPs.