Sorry for the prolific posting... but another point
I am unsure how this is handled currently, so it may not be an issue. I would recommend a long lag time after the introduction of a new weapon system (the moreso when it is revolutionary vs. evolutionary in nature) before units of these items begin to be delivered to the front. Even after serial production began, it was usually many many months before new types made their way to the fronts in any numbers. After a design freeze for production, and production start, production aircraft (for example) were required for training purposes (not just pilots, but ground crew, repair and maintenance units, etc....). All these components required new manuals, procedures, spare parts inventories, supply channels, and on "new" items all of this first time mass usage (just in preparation for combat commitment) often revealed things that needed to be changed or modified and even more time was required to make these changes.
Now, in desperation, some of these things can be rushed (and were rushed) with resulting degradations in flight profile, reliability, etc.... It would be nice for a player to have the option of making these trade offs if he felt desperate enough. Just doing the research in a given area, even if we consider it to produce a model that is ready for actual production, does not magically transform that vehicle/equipment into something that can be deployed, maintained, supplied, in the field. Most weapon systems spend less than one percent of their useful life actually in some form of combat. (An exception that proves the rule - if you were a German prop driven fighter that came off the production line in June 1944 you were far more likely to be destroyed at the factory by enemy bombing, crashed during acceptance flights from component or pilot error, crashed by a ferry pilot for the same reasons, or destroyed by bombing during rail transit as many German aircraft, particularly jets were shipped by rail to their units, crashed by a front line pilot with little experience or due to mechanical failure/poor maintenance, or be destroyed on the ground by enemy fighter bombers, than be shot down by the enemy. And you were far less likely to ever fire at an enemy let alone bring one down).
A sense of scale, particularly with things like the Me-262 are essential. Though the Germans produced some 1200+ (with another 600-800 destroyed during production) they were essentially an irrelevant footnote to the war. An interesting but meaningless technical achievement. The largest combat deployment of Me-262s, ever, in a single group was 29 committed against an American bombing raid in force on March 3, 1945. These 29 shot down 3 bombers. The greatest number of total sorties occurred on 10 April 45 when 55 262 sorties were recorded. The Germans claimed 10 bombers downed (the 8th air force records do not support all these claims, but 7 or 8) and 27 262s were lost (German records acknowledge this number). Detailed analysis of Luftwaffe and USAAF records indicate that Me-262s succeeded in downing 52 American bombers and 10 fighters for the loss of over 200 Me-262s between August 1944 and the end of the war. Even if the jet losses are overstated by 100% (i.e., only 100 lost in combat against USAAF aircraft, or even overstated by 400%, with 50 jets lost), this is not a great combat record and not all that great an increase from the records of competently flown German prop aircraft. It is questionable whether the massive out lay of critical strategic resources saw an adequate return on that investment in the Me-262.
Far from being a wonder weapon that struck fear in the hearts of the American pilots, it is stunning to review the records and see the raucous pell mell scramble to come to grips with the jets when they did appear. In fact, the American fighters were often so aggressive they were more of a danger to each other than the enemy simply by sheer numbers. And in the end, no matter what the jets did, they were irrelevant. The USA was approaching 100,000 aircraft per year in production and, more importantly, at the front the 8th Airforce was fielding, on a given day, more than 2000 4-engine bombers and more than 1000 of the finest prop fighters ever produced in escort. Total victories by the Me-262 in its entire career against the USAAF resulted in less than a 2.5% loss rate for a single day of 8th AF operations. Averaged out of those 10 months it amounts to one quarter of an aircraft lost per day to the jets - assuming full scale operations at least 1 day out of 4, that's a fearsome loss rate of 3/100ths of a percent. And this doesn't even include the medium bombers, or the Royal Air Force, or the mob of American machines under repair or in the pipeline to the front, or the other USAAF air forces in NW Europe. You stand a better chance of getting killed by a shark. A kill ratio 100 times higher would not have mattered. And it is worth noting that these aircraft were superlative in performance, for the most part, and flown by the very best combat aces Germany could produce.
LR