Sorry about the long wait.
Ok, I'll review them one by one and point out some stuff.

hax is back.rpl:
How complex your replay is is one of the things people tend to evaluate naturally, whether they are familiar with the game or not, it's only natural for the viewer to think to himself "Could I do this or not?". Your replay doesn't necessarily have to be complex to be a good replay, it can also stand out for being creative for example, or for having a unique style that people don't see often.
I broke that down for you to be able to evaluate parts like your opener+1st hit on your own.
They are really generic and reflect your long years in multiplayer since grabbing+kicking is what an experienced player would often do online while being so close to his opponent, because it's easy and "effective". Those are the exact reasons that make it a "bad" move for singleplayer. Being too easy, generic, and not that effective since you only got one dm.
I'll make use of the occasion to clearly state that single dm hits are NOT to be looked down uppon when the player is clearly looking for smooth, clean hits. On the other hand, when you're clearly looking for a powerful and fast hit, and hit Uke on a cluster of joints (like you did on your first hit), if you only get 1 dm, people are going to think that you failed to do what you wanted, and will look down uppon it.
As to why you only got 1 dm on that first hit: you need to use all of your body's joints to achieve all the speed you can if you want more dismemberments. On this particular hit, you hardly even used the knee joint. You did extend it, but it was barely even contracted in the first place, that's why it was so weak.
On the second hit, the contact was made between your shin and uke's arm. Hitting with your shin often looks and bit messy and uneffective since you obviously can get a lot more power if you hit uke with your foot, but it can also give people the impression that you failed to do what you wanted. In this case it seemed that you were accidentally too close to uke and therefore had to use your shin instead of your foot. And when your leg reached its full extension and didn't dm anything at that moment even though it hit Uke on his back, the impression that you failed to do what you wanted was reinforced.
Moving on to frame 270. Your leg was fully extended way before it had contact with Uke, so a lot of that kick's power was wasted, be careful with that.
Around that time you were also grabbing Uke for a long period of time. Usually that's also looked down uppon, either because it's too easy, because it looks messier since Uke is always glued to your body, because you're doing the same thing for too long and people they get bored; different people have different reasons, but overall not many players like to see it.

Ok, that's enough of a wall of text and in my opinion has a couple of useful tips.
I won't review the rest of the replays since that took me a bit to write and the night is short, but addressing the problem that you said you had:
-That might happen because you rely too much on grabbing. Try hitting uke in a way that his body will fly into a place where you can easily hit him once more, or hitting him with a fast combo in a way that his body doesn't even have time to fly away, or practice your ability to easily move from one place to another so you can keep hitting him even if he does fly away. You've got a lot of ways to get around that but in the end your choices will dictate your style as a replay-maker.

I hope that helped and don't hesitate to ask if you need further questions answered.