Looking at AH's aircraft speed profiles (look on the main AH page under Game Info) max speed for a B-17G is about 300 MPH True at 30k. Max speed at 15k is about 270; however, these are Maximum speeds achieved at "military power", not Maximum Continuous (or "cruise" speed) which would be much slower. But here's another "however", AH fighters are not limited in the duration of their "military power" (i.e., full throttle, no WEP) times. There should be a time/temp limitation to Mil for both fighters and bombers but we don't so I'd say it's a wash since neither bombers nor fighters are limited in using maximum power and therefore cruising at Max speed.
EDIT: looks like Eagle and I were on the same wavelength at the same time :-)
As far as having a difficult time intercepting bombers at altitude...welcome to geometry, density altitude and RL. An aircraft at altitude at high speed has a huge advantage over interceptors, even ones with a major speed advantage, trust me, I have some experience with this. While there are several reasons, the biggest is geometry. The more forward-quarter the intercept is the easier it is; however, if you're behind his wingline you are at a major disadvantage exactly as you are in RL. If you're co-alt, dead 6 on him at 6k you're 3 miles behind him. If you have a 100 mph advantage in speed it'll still take you at least 5 minutes to overtake him even if you can maintain the 100mph advantage the whole time. That's a long time. Also, most people I see think that an intercept means you point your nose at the guy (i.e., pure pursuit). Not true. You have to take a cutoff vector and put your nose well in front of the Buff to get there in the shortest period of time otherwise you're just putting yourself in a tail chase. You're also in thinner air which means you don't turn as well, have less power and bleed e faster all of which makes intercepts more difficult. I also think that a lot of your observations are based on perception, not hard data. The distance countdown is very course (i.e., goes from 6k to 5k, doesn't show 5,900; 5,800; 5,700; etc.) so it gives the impression that there is no closure, it's there, it's just small. Closure is also much less than you EXPECT to see, hey, you're in a high-speed uber fighter and he's just a Buff, right? Face it, if you're behind his wingline it's going to take time..lots of time, that's life and physics.
Bottom line is what we have performance wise is relatively accurate and the bomber formations are realistic. Just as in RL, intercepting Buffs has more to do with geometry and altitude than anything else. The key is get ahead of and above the Buff and prosecute your attack from there (diving from directly above also keeps you away from most of those nasty little .50cals). I have 114 Buff kills this tour, only been killed by bombers 12 times and 95% of my kills are in a Hurri 2C. Bombers don't seem too fast or powerful to me.
All that said, I'd be all for finding a way to stop Lancstukas and reimplementing the full calibration requirements including target altitude, tracking a ground tgt, etc. It would also be nice if someone could figure out how to severely penalize those that bail immediately after their bombing run (or when they're about to get jumped). The .50cal's don't bother me, it's the fact that these bomber bozos are so gamey.
Mace