I think I have a good idea. What if they added something that you can do when being knocked back?
Like, Guy A hits you. Guy A swoops in to nail the "Two-fer," and you, Guy B, have a move that can be executed with precision timing (pressing a key at the right time) where your character would do something like kick away from the attacked player, avoiding the hit?
Just a thought.
As for you missing the combo...I think it's fine that you miss it but I guarantee if it got done to you all the time you would be glad to see it gone.
In 1.1 the system wasn't better but it was more rare to see the unblockable string of hits. My gripe mainly with 1.2.1 is that almost everyone does hit-hit-beam, some do worse than that. It's pretty cheesy, because the math of it is really simple:
If Guy A and Guy B fight, both with only simple melee, let's say Guy A is me and doesn't use that tactic. Let's say Guy B is someone who does. Literally speaking, Guy A has to land 200% as many hits as Guy B to score a kill. If there's terrain involved, the double knockback makes that percentage even larger, and this is not including the ki blobs or generic blasts.
I still maintain my theory that this can be fixed by making the second hit have some kind of trade off, like a much shorter recovery time or something. There are a lot of ways it can be looked at.
Either way, 1.2.1 makes me happier to play now. With the tweaks to advanced melee I can actually deal damage worth dealing in response to players who use this tactic. Plus it's sweet when you land a 14hp kick to the chin; so satisfying. Hehe.
I know most people don't want to do anything to change the "exploit" as I often call it. I don't really think it should be out of the game; I wish I could come up with a good way to balance it out so that it could stay but not be so aggravating.