You have to remember that allies can just ignore teching and go full scale commander call-in play. As axis you don't have that choice.
@RedT3rror artillery for OKW only? And not for ostheer, who don't have any mobile artillery (as the platform artillerys are very easily denied.) Panzerwerfer I don't count as artillery.
T34-85 and easy 8's are all tech tied now.....so yeah.
Not sure giving OKW long range artillery would be a good idea considering the trouble we had just with leigs. Might be better on ostheer as you suggest but they already have static artillery.
@OP
You also need to consider that the allies have a greater variety in vehicles because there are 3 factions each with very different play styles. Then there is the fact that many of the allied vehicles simply aren't worth using at the moment.