I was thinking about it in a different way:
Elite unit: Att: 1 Def: 2 Move: 1 cost 4, receive +1 att when paired with Art (same as Inf) or with an Arm (special ability).
After the first round and the rest of the battle, they give +1 att to Art or 1 Elite unit.
So after the first round (of amphibious assault and coastal bombardment), if the Elite unit survive the defender rolls, it provides better targeting for Art (att:3). If their is two Elite units together, then both have +1 Att, thus getting 2 E. units Att: 2 Def: 2, as long as they are paired.
Thus, for example, after first round of battle,
1 “marine” unit gets Att:2 and 1 paired Art get Att: 3.
Also this unit paired with an Armor will get this same attacking punch
Marine Att:2 and Armor Att: 3 on the very first turn and keep it after.
(It can be a way to represent the used of some kind of amphibious vehicule to get on the beach and a better coordinate work.)
The idea is that unit is better trained to work with other kind of arms on the battlefield.
Alone they are almost like ordinary Inf, but with others, it becomes a more deadly and efficient group.
So, when a US Elite unit (the marines) makes an amphibious assault with an Arm, at first they Att: 2 instead of only 1 for regular Inf.
I don’t want to give an additional +1 att. to Arm, because the fantastic “4” seems restricted to bomber and BB in many A&A versions.
Since, this unit already receive a +1 Att when paired with Arm on the first round of a battle, it can demonstrates the better coordination of “Marine trooper” with tanks during an amphibious assault and after.
And it is possible to put on a transport 1 Elite Unit and 1 Armor, and get the same offensive punch (2+3) than 1 Art and 1 Armor, but you cannot put both units in the same transport.
Another tactical interest over Inf+Arm (1+3) at 9 IPCs!
USA will certainly see what’s in it for them.
I also prefer to give a basic Att:1 because I don’t think that an Inf unit alone, even better trained, was as deadly as an Art unit or the defending troops waiting on an island, not until they get a real foothold. Or, unless they were helped by Art or Arm on the first round (almost like any ordinary Inf).
Is this historically accurate about how the marines works on the battlefield? I don’t know, but I hope.
In game terms, I think it keeps the balance.
You can chose: Inf+ Art, cost 7 for 4 attack points and 4 on defense.
Or you can prefer Elite + Art, cost 8 for 4 attack points on first round,
5 attack points after (if they survive the first
round) and 4 on defense.
This match of Elite+Art (8 IPCs) can be as effective on offense than Art+Arm (10 IPCs) but not on the first round and move only at 1.
Also, on defense, it’s only 4 points instead of 5 for Art+Arm.
Though, Elite+Arm (10 IPCs) can be as effective as Art+Arm (10 IPCs) for the same cost.
And alone, Elite unit is no better than regular Inf but cost 1 more IPCs, thus it keep Art an interesting buying because alone Art: att2/def2 vs E unit: att1/def2.
So nobody will buy only this Elite unit but it will keep interest in buying more Art.
What do you think about this different way to look at the marines?
Now I think we can introduce them in 1942.1, 1942.2 and even 1940.