  We recapitulate the latest results on the class of the simplest SO(10) grand
unified models in which the GUT-scale symmetry breaking is triggered by an
adjoint Higgs representation. We argue that the minimal survival approximation
traditionally used in the GUT- and seesaw-scale estimates tends to be blind to
very interesting parts of the parameter space in which some of the
intermediate-scale states necessary for non-supersymmetric unification of the
SM gauge couplings can be as light as to leave their imprints in the TeV
domain. The stringent minimal-survival-based estimates of the B-L scale are
shown to be relaxed by as much as four orders of magnitude, thus admitting for
a consistent implementation of the standard seesaw mechanism even without
excessive fine-tuning implied by the previous studies. The prospects of the
minimal renormalizable SO(10) GUT as a potential candidate for a
well-calculable theory of proton decay are discussed in brief.
