A moderately wealthy player would have no difficulty dismantling a chunk of his harvesting fleet and building dozens or hundreds of probes to accompany his attack fleet for a major invasion, then destroying them all and rebuilding harvesters/cargo ships. Probes can also be made very fast, so if combat takes any length of time, planets could keep chairing them out. Also, because you're maxing your count with cruisers doesn't mean other people are (I am not), nor does it mean you would under the new system. All you need is a couple of large ships, and many probes, and you have a good chance of surviving and winning every battle. Your probes take most of the damage, and you can rebuilt them almost instantly at negligible cost.