I do not think that KGF (or KIGF) is dead. Infact it could possibly be even deadlier since Germany can’t send inf directly to Ita, they have to go through WE or Blk first.
The Axis may get an economic lead, but it should not last long. Japan will always be strong, but this is no different than Classic or Revised.
If I go KGF I’d go with the heavy shuck from Wus-Wcan-Ecan starting in round 1 (similar to my Revised strat). You buy something like 10 inf, 1 ftr, a bom + inf could make more sense in AA50, but as long as you buy 6-8 inf for Wus you are good to go to start.
Can Japan annoy you in Ala later? Sure.
Will it be effective? Maybe, maybe not. Depends on the US player.
No longer can Japan land directly into Wcan. And can they put a dent into the 8-10 unit shuck? Not if the US player is good. For the US Inf + ftrs (or boms) is a killer deterant.
The Allies can do a Heavy Afr landing in rd 2 and then shift the UK to Sz 6 while the US helps in Afr and puts a token threat on Ita.
Japan cannot get to Mos until like rd 5 (perfect scenerio), but can’t have a sizable army until rd 6 or 7 or later. This gives the Allies 6 rounds to sink the Ger ships, sink the Ita ships, 2-3 Afr landings, reclaim Kar for Rus and start dropping either 14-18 units in Europe or splitting them between europe in Afr and this is all very doable.
The US can get inf from Ecan to Mos in 4 turns, and can get inf from Ecan to Cauc in 3 turns. Both are shorter than Japans supply lines.
Also, once the Ita fleet is sunk, the US, if played right and they wanted to, can turn its entire income to Japan now since you should still have 3 shucks that are ready for Europe or Afr and if you know Germany won’t be able to take Mos in those three turns.
Depending on how you play and setup the Allies sometimes the Mid-Pac switch (US switches to Pac strat mid game) is better and sometimes it is better to just finish off Europe, depends on the game and Ger inf stack in the core of Europe.