I think the whole ''does the DV from boxing/kicks stack'' is the same reason a troll gets his +1 reach in melee if he's punching or kicking(this is without any maneuvers.) Even though a troll(2.4 meters tall nowadays it seems on average), probably has the same leg length as a 2.1 meter tall elf, ork(i might even say shorter...and if I recall, that super-tall Elf metavariant does NOT get reach), or even human because of they way they're built, their arms are the definite ''long limb'' on their body. Unless the artwork managed to mis-draw them every single time, their legs are not super-long and probably technically shouldn't have a reach bonus, much like a elf or ork. But, since unarmed is lots of maneuvers, I assume that they get the reach because they are using their arms as well.
I recall, back in SR3, a buddy of mine who actually ruled trolls got the +1 in melee as usual...unless they actually specified they were only kicking. They did not get it at that point. (it didn't stop anyone. We just had lots of troll boxers and troll weaponmasters instead.

) I can see why he ruled that though; I have seen tons of pictures where their legs just aren't that long. They always got it holding weapons, in any case. Some people may not like that houserule, but it didn't bother me when I heard it(and I was playing a troll...but he DID have a scythe and a hand spur so it was kind of moot for him anyway.)
Yeah, ever since the kick attack maneuver came out, there's been a lot more...kicking styles being used. (to be fair, I was abusing kicking styles on several of my characters just for their looks for ages, as do others no doubt, now they just give you a reason to.

) Then again, though, with the ''unarmed as lots of moves'', someone with Kick Attack can still punch. And I assume if someone does a bunch of maneuvers, I might describe it as a ''feint, a couple of punches, and a round kick to the stomach as they reel'' or something. But I guess people take all the kicking styles with Kick Attack just to ''be safe'' and keep the reach bonus. Again, like my friend's houserule above, I'd assume they'd always have it going unless they either specified they were only punching...or, for some reason, could only punch.
Then there is the case of things like Satyr Legs/Optimized Punching Cyberlimbs, where the people only seem to get a bonus to one of those particular manuevers.