Probably not the answer you want to hear, but wait, be patient, and most importantly provide objective data to Wyrd of the issue. A lot of things moved at the same time between the edition switch, and a lot more people are testing them now then were when they were moving. The early release of a GG shows they are paying attention and working on it. They fixed some issues in it, I'm sure when they feel it is the right time to do an errata they will fix some more (to be clear: the time the devs think it is appropriate to release an errata is probably different than the internet hive mind, and for good reason)
In game, punish him by taking taking expendable models. If he doesn't have a worth while target to shoot it'll feel bad to pop a 5 wound model because he has nothing else to do, something he may not be able guarantee without cheating anyway. But to date I don't have any tech to protect any high cost model that doesn't already have insane defenses built in.