Historically the USA joined WW1 in Spring 1917.
TLAGO correctly illustrates the woeful US military unreadiness, as it requires essentially a year before the first substantial contingent of Doughboys can appear in Europe.
Assuming a historical declaration of war this matches well, with the US armies arriving to fight in Spring, (Chateau Thierry?) Summer (St Michel?) and Fall (Meuse-Argonne?) of 1918.
But the game does not allow any economic aid by the US until the first Army is in Europe. At first glance this seems reasonable with them able to “lend” through 1918. However, on closer analysis of the turn sequence this in effect restricts them to a single turn of PP transfers.
In Spring 1918 they may transfer PP at the end of their turn, which occurs after the Western Allies production, (Maximum 4 to UK, 4 to France, 1 to Italy, 1 to – presumably refit the first US army, 4 wasted?). This will allow an unfettered offensive by the Allies during the next turn as they will receive these points at the end of their Summer turn, and so be able to refit extensively.
But Lending after the US/Eastern Allies Summer 1918 turn is nearly pointless, as the PP’s are not received until the Western Allies (and the Germans) have taken their final (Fall) game turn. The only possible use would be to refit in places where an (unlikely?) Austrian offensive could make a difference.
Now the game does potentially allow an earlier US entry, but they can also appear later and in practice the players can do very little (nothing at all for the Allies) to influence this. This means that at USA which declares war in Summer 1917 (or later) can lend no economic aid at all!
Considering the historical situation, although it was initially somewhat haphazard, between declaration of war and July 1917 the US actually lent almost a quarter of a Billion GBP to the various Allies (slightly more than the UK in the same period). The inter-Allied finance policy which was settled later in 1917 allowed for substantial monthly advances to each of the Allies to defer war costs.
Now Dollar (or pound) loans are not the entirety of Production points, however when one bears in mind the all US war lending at this point was only and exclusively for the purchase of “war equipment” from US suppliers, it is clear that this represents a very substantial contribution to the war effort of all concerned. [To give a little perspective, the British, lending slightly less at this point were financing about two thirds of the French war economy, and nearly all of the Italian and Russian war efforts].
To the nearly exhausted economies of the Western Allies the US economic aid was a huge and immediate relief, all of which preceded the actual military involvement of US troops by many months. Indeed, I have read that President Wilson initially hoped to be able to assist the Allies only economically, and avoid sending any American boys to fight abroad.
I would suggest therefore that restricting the US to PP transfers only once an army is deployed into Europe does not well reflect history, or the vast support which was an immediate aid to the Allies.
Clearly some time must be allowed to reflect the US gearing up its industry, and your mileage may vary based on perceived play balance, but I would suggest allowing The US to transfer 1PP for each Fresh army on the board.
Thus (historically) 1 in Summer 17, 2 in fall, 3 in winter.
This is hardly an overwhelming contribution (you could indeed argue for double those numbers), but should at least give some representation of the immediate benefits of US participation.
The US declaration had one other immediate impact. The blockade of the central powers became more effective literally overnight.
First, since the US itself had been the neutral power whom the Allies were most concerned to avoid offending (and several tens of millions of dollars of trade was done with the central powers prior to the declaration of war), stronger measures could be taken. Secondly the US, having joined the blockade, was far less concerned by the scruples of other neutrals in its enforcement of its position.
Under 8.2.2 the Germans gain 1 PP for breaking the blockade, essentially indicating that the existing Allied blockade is costing them 1PP a turn (at least). Given the stringent US position, plus the loss of US trade itself, it does not seem unreasonable to suggest that the Germans should lose a further 1PP per turn if the US fleet (spent or fresh) is in the blockade box.
Taken together these two variants allow a more immediate US contribution to the war and ensure that even a late entry will still have at least some economic impact. Following a historical Spring 1917 declartion this would let the US bring an additional 6 PP to the party while taking 6 PP (?) off Germany.
How far these suggestions would impact on play balance is hard to assess, but certainly there seem to be devotees to suggest that the Central Powers can swiftly overrun Russia and then overwhelm the West, implying an existing pro-Central powers bias.
Very interesting observations about a game mechanism that is obscured by the flow of the game. I hadn't realized how limited the US contribution is as a result of the game mechanics. I'll check is out myself to be sure, but thanks for noting it, and thanks for the suggested fixes.