Yes, now if the proposal would be not to redefine the semantics of UB (as the post to which I replied suggested) but rather about specifying that buffer overflo

Yes, now if the proposal would be not to redefine the semantics of UB (as the post to which I replied suggested) but rather about specifying that buffer overflows are UB1 and integer overflows are UB2, and UB2 means something different from UB1 (perhaps identical to implementation-specified behavior, perhaps something different), then that could be reasonable.