In my experiences online with Zod thus far armoring a b3 or f3 seems to be a pretty good option but not always the best. Its true that they made him so slow that punishing anything is just ridiculously difficult unless its something really unsafe. Its like I said in an earlier post. I don't think Zod was thoroughly tested among the entire cast. I think there was a lot of Zod on Zod action because Zod only really seems to punish Zod and a few others. The frame data says these moves come out at this speed and that but when I read something easily, block it, and go to punish and get caught because Zod decides his foot can take its sweet time reaching a character then I have my doubts. Also I see a lot of people saying d12 but let's be honest, that move has very little range and there isn't much combo potential off of it when it really counts. You're not going to block everything and so between their huge combos hitting and that whee little punish combo hitting who do you think is going to win out. Zod needs speed and a patch on his trait. I don't know what they were thinking making him this slow. Sure the moves start up in a relatively decent amount of time but go hit f12 on Zod and then go hit say f23 on Superman and notice the huge difference. And the word is out that Zod is slow, no one fears you unless the trait is up or if they have wickedly slow reaction speed. Now combine Zod's already slow speed with online lag and you've got yourself a formula drastically in the opponent's favor. I am not saying he's unusable because I do main him and I'm not saying he is entirely incapable of punishing but when we match him up against the countless Supermans, GL's, BA's, Aquamans, and other favored characters out there, he doesn't exactly have many options. But some times you can catch them off guard with a well placed HB. And yea GL, Superman, Black Adam, and Aquaman have been really touch match ups for me. O and Batgirl can be a bit of a pain.
Edit: Ok so for punish options. To play Zod you need to know the game quite well. No one has mentioned the reversal window. Rarely do we get stuffed by lows, or at least in my fights, when trying to punish. I started using the reversal window to pull out Zod's parry to get quick little damage and breathing room. Also the side arm has the same amount of start up as the ground Zod Charge. It stumbles the opponent backwards and if you are consistently faster than them you can dash right in into a full combo. Lots of testing to be done with the guy. He is still pretty new.