It's hard to take a "threat" from Russian conventional forces seriously. The Russian Army for instance has about 40-80,000 first rate, well-trained and funded professional soldiers (i.e., the "little green men" who invaded Crimea). The rest of the Russian Army is a second-rate conscript force where corruption and abuses are rampant -- drastically and negatively affecting morale. In any serious, sustained conflict against just about any NATO member, the Russians would have serious problems. If we armed the Ukraine, they would have serious problems against a revamped and experienced Ukrainian force flying Western aircraft and driving, say, M-60A3 tanks and modern NATO fire control systems...
Yes, the Russian Air Force does have some excellent aircraft featuring thrust vectoring and the like, but they simply cannot afford to field them in large numbers...