My only real criticism of the new tree is that it makes civilian labs even less important that they were before. Lets face it, with all the cool new toys you get from military who's going to go beyond trade ports in the civ tree now?
Other than that, being able to research more at once is good. And really, most of the stuff in defence is specialized enough to warrent its own tree. Most of the old techs that were moved into the new tree were never used. By not holding up the queue for other military reasearch anymore, they might actually see some use now.