It's not that there's no models for them, we can make them if we didn't have them and they're just commandos, so we do have them. What I'd said was about them not really looking any different. If we're only having one Commando squad as heroes (and we are) Delta Squad makes much more sense- they're more prominent, and they also stand out from other commandos. The Republic is chock-full of possible heroes, so I don't know if any of Skirata's group really qualify as the must haves within their classes, especially when they were more concerned with Skirata's side stuff. We're not trying to make Hero Simulator here- there's dozens and dozens of Republic heroes we could have, versus about 15-17 we've identified for the Clone Wars period for the CIS, and while the Republic will be more hero-oriented, we need to stay reasonable. We don't want it to devolve to just giant fleets and armies of heroes to the exclusion of other units. Once you get past the actual must-haves, as in, the people most important for the overall storyline, and then the prime examples of any other category (ie, Delta Squad representing the Clone Commandos) there's only so much room for characters who are less important to any major storyline and are mainly just popular among certain portions of the fanbase, especially considering Skirata's group really was Skirata's group and far less integrated into the actual GAR.
Really though, because of how many possibilities there are, no matter which way we go, there's probably no individual person who's going to be entirely happy with whatever subset we choose.