The main part I don't like is the guard between the blade and the handle. Also, the older ones seem to have nicer (darker and smoother) leather on the handles. I'd prefer more of a blued finish. I had a SOG S1 Bowie, I really liked it...
First, +1 on the D2 Extreme if you want "something like a KABAR". Doesn't match all your specs exactly (grey epoxy coating on the blade instead of black "whatever" and Kraton rubber instead of leather on the handle) but otherwise matches up and would work well.
The guard on a 1219C2/USN MK2 is just what it was designed to be - functional, inexpensive and quick to make and produce. Kabar tries to remain relatively true to the original specs, just the pommel is different so as to maintain integrity between identifying an original WW2 1219C2 and a modern version (the 1217).
When you talk about the "rougher" leather handles, we have to ask which "Kabars" were you looking at. All of my personal 1217s came with pretty smooth leather handles. Not as smooth as any of my 1943 first production run low mileage KABAR/CAMILLUS 1219C2s/USN MK2s, but those have had 70+ years to "wear-in".
If you were referring to "other "Kabars", say a late Camillus version (post contract termination - 1983 to 2007 bankruptcy), yes, those "Kabar" handles feel very rough to me. So do the current production Ontario versions. And talk about rough, the CASE XX reproduction (which they never produced a single knife of during the war except for 2 prototypes) are rough as cobs.
The darker, smoother finish you see on "older" versions is probably from use. Sweat, skin oils, rain, whatever will darken the leather rings over time. Use will also "slick down" the handle surface from frictional usage handling. My user 1217s started out dark brown. Each is now a slightly different shade of "darker brown", as each gets used a different amount.
The 1281/1282/1283 D2 Extreme has a different style guard and pommel than the 1217. Some people like them, others don't. The handle is also made of grooved Kraton. This material is very grippy even in the wetest weather and cleans up easily. It is 0.8 ounces heavier than the 1217. The only differences between the 1281/1282/1283 are the black sheaths. 1281 comes with a Cordura nylon sheath, 1282 with a plastic hard shell sheath and the 1283 is leather.
YMMV.
ETA:: The 1281 is partially serrated. Some folks don't like that, some do. I can take it or leave it. If I had to cut more line or rope, that might be important.
