...Uh, what? You can EASILY combo off 2 1 pressure from the ground. It's a safe block string, and it's hit confirmable into either a freeze or 2 1 1+2. Against the majority of the roster, you can just keep pressuring with 2 1 and add on the 1+2 at the end if you see them try to get out. Even if the 1+2 is blocked, you can safely jump out or do a jump back divekick. You get a mixup here, because if they attack or block, you get a safe divekick. If you anticipate a jump, you can just uppercut them. You can also mix in 3 3 EX freeze if they aren't blocking low, and if they ARE blocking low, just throw them. No one seems to realize that you make yourself vulnerable to throws when you commit to blocking low, which is why Ermac's F4 mixup is so strong.
First off, you can easily get a freeze from halfscreen to fullscreen distance if your reads are tight. Often times, you should be throwing out an ice ball on wakeup just because it's safe, it's free meter and it's good oki. If you have time, you can throw out an ice bomb just to get them off their spot or keep them out of yours, then throw in the ice ball to keep them at bay. There's also nothing stopping you from using EX freeze from fullscreen, because his EX freeze is functionally identical to Sub Zero's.
The parry IS absolutely godlike if used sparingly. It gets you out of frametraps, it completely invalidates the crossup punch and the EX freeze grants you a full combo punish. As long as you don't abuse it to the point where your opponent will actively try to circumvent it, the parry is a godsend.
The slide is better than okay. If you seriously have any issue with this, you're asking for too much.
There's really nothing you can say to defend this. Cyber Sub's only real hard matchups are with Kitana, Raiden and Cage, none of which can't be managed. He has all the tools to handle any other situation, and you'd rather make excuses than use them. Truthfully, I find it pretty amusing that this comes just two weeks after you say you're going to be repping the character at Evo.
I've been told I have one of the best Cyber Subs out there, and you know who I blame when I lose? Myself.