Personally, I tend to agree that taxonomy shoud include paraphyletic
groups, BUT only if they are useful and make a meaningful distinction
between groups with a distinctly different suite of features or habitats or
whatever. This certainly does not describe "Thecodontia". What do
aetosaurs, rauisuchians, phytosaurs, ornithosuchians, erythrosuchians,
proterosuchians, proterochampsids, and Euparkeria all have in common with
each other that unifies them and makes them significantly different from
both crocodilians and dinosaurs?