I think most of the appeal of the H2 odst is that it's just so simple...
Although I have been seeing more people mention that they'd like a higher def H2 helmet, so maybe after I clear up some projects and get some free time I could eventually get to that...
I think a lot of people are also pretty unsure about how to finish a Halo 3 set of armor, so they're waiting for someone else to finish and post how they did it. Building the armor itself is pretty easy, but the undersuit and armor mounting system is a lot more complicated than it looks. Well, making it look like the weta one, anyway.
I've received a ton of PMs asking if I ever worked up a drawing for a undersuit/ strapping/ mounting setup for the weta odst, but I haven't gotten to it yet and probably will not for awhile.