I suspect a book could be written on how time and creative minds led Universal Soldier from being a kind of shitty Terminator 2: Judgement Day rip-off into whatever mad genius that is Universal Soldier: Day of Reckoning. I doubt anyone will bother, but I'd read it.
I wrote Universal Soldiers a while back, covering my own brief thoughts on the incremental path by which the first three movies move from kind of shitty to kind of fun.
John Hyams - check out John Hyams Is the Best Action Director Working Today by Nick Schager - carries over as director from Universal Soldier: Regeneration, but still takes it a few steps forward all around, not the least of which is in fearlessly committing to its concept, which I've stated many times - is the biggest problem with low budget genre moviemaking these days.
I'm still considering myself on hiatus from reviewing things, and while I do have a couple of more things I consider I "owe", for instance a conclusion to Star Wars saga, I think I might be happier keeping that the status quo for a while with so much going on and a desire to focus as much of the writing energy I have available to my screenplay. If I made you at all curious, however, check out Outlaw Vern on Universal Soldier: Day of Reckoning.
I'll also toss out, while I'm modestly on the subject that, while not as dramatic, in my opinion, Death Race: Inferno continues moving that series from competent, overcautious theatrical original into something that takes a few chances and really has some fun with its concept.