Although it's good to point out what a fighting stance should actually look like I have to disagree.(but no offense intended jams, very valid point Smiley)
The RiverCity pose is very generic, which actually works well in game since the player does other things than fight.
Here we see the player shopping, talking to a child, and engaging an enemy:
I have to disagree with your disagreement. XD
Even though the RCR pose isn't a full-blown boxing stance, it's
close enough to read that way when faced with an enemy. The pose looks
even more like a fighting stance, because for 95% of the game, it
is a fighting stance. The little text bubble comic you did was cute, but he still looks like he wants to punch that girl in the mouth, hahah.
The problem I had with your edit was that even though it's slightly generic like the RCR sprite is, in that it's not a true fighting stance, that unlike the RCR sprite, I don't feel it could serve as a fighting sprite, even with enemies on the screen. He looks a bit angry, sure, but it's not a pose I see him fluidly attacking from. Or at least he shouldn't be.
What he
does look good for, in my opinion, is one of those big slow-type enemies. The one's that you have to beat on for like ten minutes before they die. And they only attack once in awhile, doing a huge charge-up/telegraphing animation before throwing a punishing haymaker.
So I'm not saying your sprite is bad or has no place in a brawler. It's just that the RCR pose is closer to a believable fighting pose the main character should be using, since the main character should react to input and throw punches quickly, usually working into combos. Your guy is fine (and really nice looking, actually) for one of the bigger slower enemies who takes a lot of punishment. =)
And again, note that my whole argument is based on the assumption that numlock doesn't want do have different poses for different actions. Like you said, if he's willing to animate multiple poses, that'll obviously always be the best option.
Numlock, I'm liking his new pose, but his face looks too happy to me for some reason, even though his eyebrows say he's angry, hahah!
And is that your first walk cycle? If so, that's really impressive. If not, it's still looking pretty good. =)
Now that you have his basic walk movement down, you should add some secondary animations to give him some weight. Have his fists and hair lag behind a bit when his body falls, and then have them come back up. Have his hair move around. Etc, etc. It'll make him look more lively.
Also, small, crappy edit for you:

Just to show you what I meant when I said you might want to put his left hand a bit more than his right. Your newest one is good too, though, so I'm not sure what you want to do. If you want to do a full-blown fighting stance, Pixel's updated RCR poses are better than mine, anyway. Those guys were/are pros for a reason, after all. X3
Also, I just have to say that I applaud your design decision to have the main character walk around in boxing gloves all day. It's awesomely silly and retro of you.
Nothing says "I'm gonna kick your ass!" like walking around town in boxing gloves scowling at people. This guy means business! XD