I think having 1 Assgren squad out can be useful when covering the flanks at times, once an Assgren squad reaches vet 2-3 they gain the much needed armor bonus and can actually scale somewhat vs shocks, especially when you use their special grenade ability. Overall though investing in more than 1 Assgren squad can literally weaken your ability to scale into the late game, which is nice because you can't spam them like people were able to over a year ago.