Usually combined with the flak truck and/or mgs they work decent (not great) against suppressed squads. Hollow charge barrage ability also does decent dps against armor. Since OKW at guns sucks its nice to have long range AT.
More importantly, T1 allow OKW to quicktech T3 and give FHQ healing and reinforcement which are very important in team games.. Imo unless big patch changes happen with the metagame evolving T1-T3 openings will soon become standard in 2vs2.
Stuka is best ofc but T2 is a huge fuel sink which delay all the good T3 units OKW get to counter many different strategies. With the guards button nerf OKW T3 are more very effective vs Soviet T1 openings than T2 with luchs, obers and panther. Obers also can fire lmgs on the move which can kill snipers in one burst.
Stuka might seem good against soviet T2-T3, but once the T34-76s come out it easy to lose the stuka if caught offguard without volks shreaks defending.
Stuka is primary effective in team games on large maps where allies can have trouble hearing the stuka firing the missiles if not zoomed in correctly.
On the small 1vs1 maps, stuka are easier to dodge and the fuel investment leave OKW vulnerable to a tank push.
2vs2 double OKW vs double soviet, stuka investment is also very risky without a pak43 to defend against a T34/85 tank spam where all you have is pumas and volks. OH+OKW, stuka could work if OH defend well with pak40. But in 2vs2 random I rarely see OH players support the OKW player well with pak40 guns.
Stuka is abit overrated because its very situational and depends alot on maps and correct timings. Get the stuka without good timings and map awareness will result in many lost games against good players that have good timing attacks with medium tank spam. Personally when I play 2vs2 random I hate when the OKW player goes Stuka first because then I have to babysit OKW with pak40 (if OH) and or pak43 or its gg once the allied medium tank push comes. Double soviet with fuel caches can make very strong timing attacks with 4-6 T34-85 tanks when all OKW player with stuka have is maybe 1-2 pumas. Good luck defending against that if caught offguard. Instead of the stuka, double OKW could have two panthers out in time to deal with allied medium tanks (or one saving for KT and stall with pak43).
