Now that people can't kick after landing the 1h attack nudge, it doesn't seem so OP now. A "free" hit is really only possible with perfect positioning and 100+ speed weapons (typically swords with weak cut), and nearly impossible with the blunt weapons that can knockdown and lead to multiple "free" hits. Rusty could probably answer in more detail, since he was the worst abuser of the 1h attack nudge+kick combo right after they added it. I don't think I've even noticed him nudging after they put kick on the same cooldown; and if anyone could get a free hit out of this nudge, it would be Rusty.
You can get a free hit off an attack nudge and you can also get a free hit off a regular nudge. I find it's easier to land a follow-up hit on someone without a shield. Probably because most shield users practically keep the RMB taped down. Since people without shields rely on footwork and reflexes, it's easier to throw them off their game. Still, I think that both are too risky to use against a halfway skilled player.
Both nudges require you to be facehugging the other person. Even in that close of range, nudges still whiff fairly often. Probably because they have such a small cone-of-effect. The attack nudge is also
incredibly slow. You can throw an attack nudge at someone and they can still swing and connect before your nudge does. They'll still get nudged, but you'll be hit and staggered anyway.
Also, the only way you can score a knockdown with a nudge is if you are 1h-no shield, but I would say that whenever you happen to get a knockdown it is entirely accidental.
For example if someone kicks, you can knock them down with a straight nudge. Most of the time you get kicked when charging someone with a held attack. So in this scenario, you need to anticipate the kick, drop your attack AND hit the v-key and hope that you are close enough to them before they start the kick. Then if it actually works, you are stuck with a long cooldown. Or you could just hit the much easier to reach "e" key and get a knockdown without having to worry about a cooldown afterwards.
The only other way to knock someone down is if they are holding an attack and walking backwards and you do an attack nudge. If someone is moving backwards with an attack chambered, you are most likely blocking. To nudge, you then have to switch to an attack and hit the v-key while hoping they don't decide to kick. Or you could go for a chamber, which is also less risky.
Honestly, I'd prefer to just not nudge and use a blunt weapon. Much easier to get a knockdown with that with much, much less risk.
Nudge by itself is good tool to knock people off their game, but it's penalties make it not worth it in most situations. It works best against terrible players, but I can kill them faster without taking the time to nudge.
I like the idea of nudge, but it could use some improvements. I don't think that will ever happen though. Mostly because if it was, we would all drown in the tears from the vast majority of the playerbase. It's just funny that the majority of the player base think that kicks (which have relatively low risk and high reward) are fine, but nudges (which are high risk with relatively low reward) are overpowered.