Yeah blobbing dp cons into hmgs and hit the I win button sounds awesome.
Hardly an "I win" button since Hit the Dirt still has all the downsides of the delay in canceling it and exposing your squads to grenades (unless you retreat). Just a thought in that it might make the commander actually viable. Though I have no doubt that some players would inevitably try to blob DP Cons.
what was Guards damage vs. vehicles before and after this latest change?
It'll be the same. They essentially just nerfed them vs. infantry so that models get sniped less ala Dank Hunters cheese.