I would actually give a slight edge to Robo-Ky, but it's definitely no more than 5.5/4.5. This used to be one of the most common fights I played, but our Robo-Ky mostly plays BlazBlue now.
I mostly disagree with Watches about the dragon punch. It is not really worth worrying about. I mean sure you will pretty much always have to bait it at every turn, but that's not difficult anyway. Just look for him trying to tick throw you, and look for his dust... And any time he could jump, be on the lookout for TK FB into an air normal, as this is his fastest overhead. Learning to block his dust is actually not difficult - Robo only has a few ways to go into it. Just go into training mode and record Robo doing several strings into Dust and examine how you can see Dust in all of them and block it on reaction. Him going for tick throw is somewhat similar - if he ever gets to close to you (especially off of his 2k slide) he may be going for a tick throw. If he times it right, this is ambiguous with a gatling to laser, but it still doesn't matter because you should be able to react to the end of his slide. He may go for command grab at other times but the only time it's really actually scary or hard to deal with is during his corner pressure because it is a way to end it that isn't dust, and you really want to not get hit by dust as the missile loop may kill you or dizzy you. TK FB to instant air normal is not unreactionable, it's just hard and you need good reaction time. Luckily, the spark is unmistakable.
Oki is kind of a whore to do against Robo. Unfortunately, Robo has a free way out of a lot of Axl's oki, as he can just sit on the ground and laugh to delay wakeup if he thinks you're going for something like crossup kokuu or bomber or whatever. I am pretty sure you can just go for a safe air normal afterwards as long as you didn't do something too laggy, which is not too bad, but he probably will not bother laughing if he knows the matchup well in this case as it doesn't help him. If you can't approach in time for a safe air normal, a well-spaced 2H is probably the best option. This is basically going to put you advantage if he does anything but DP, but if you're well-spaced you'll clash and then you can just special cancel to rensen and gain pressure. Really, if you try this, you should just always act like it's going to clash and always go for the special cancel to rensen, because it's not like it's going to come out and be bad for you if it doesn't clash.
Luckily from neutral is much more to your advantage. It plays like a lot of fights, really - Axl has pretty good pokes. f.S is good, 3P is good, 5K is good. As long as you keep your spacing right, it's hard for Robo-Ky to do anything.
When you actually get advantage, Robo doesn't have many tools to get out. He doesn't take a lot of damage and he's hard to combo, but he's still just any old character and his only way out of pressure is instant block or DP. Instant block should not be a problem if your pressure is solid, and DP is not a great idea because it's baitable and you get way more advantage off of baiting his DP than he gets off of hitting with it. This is just a matter of not doing stupid things. His defensive capabilities are really nothing special.
Also, it probably doesn't need mention, but watch his tension at all times. If he doesn't have tension, just rush him the hell down - his moves all suck, and his dragon punch doesn't have invuln. If he doesn't have a lot of tension, you can poke him out of his missiles and get a combo. A smart robo will probably not even bother with missile at this point because Axl trashes him so hard if he tries it, and you can use that to your advantage. Similarly, if he doesn't much tension (or if he has too much tension) then dust becomes less of a priority for him to land because he can't missile loop; if he doesn't have enough, watch extra carefully for the command grab, and if he has too much watch for him trying to shed tension.
Special mention goes to Robo-Dash, which makes midscreen Rensen when he's approaching fantastically unsafe. If he does it from far enough away, it's reactionable with high Tenhouseki, which is going to be your best way of countering it. If you can't do that in time, just IB. You won't be able to do anything off of it, but he won't have advantage. Also, even though he's off the ground during it, you have to faultless it in the air. It is pretty important not to get hit by this move, as he gets free tension and that's not really that cool.
If he's on the mat, pressure him off of it. Rensen works pretty cool if he's only slightly on it. Just don't anything dumb. Not doing stupid things is pretty key to every matchup, but especially the Robo-Ky matchup. He has a lot of ways to punish you, but if you just play tight, it's not really that much of a disadvantage.
FRCing in lag isn't hard <_< Well, it depends on what the move is. There's some FRCs you can totally time based entirely on animation (Pot Buster, Ky's throw, etc.) But a lot of FRCs are pure muscle memory, and those wouldn't be affected by lag, just as long as the framerate doesn't drop.