Hey, long time lurker here, registered a looong time ago but forgot my username/password and had to register again now.
Anyway, I'd LOVE to see the pop-up window from CM:BB and CM:AK again (never really played CM:BO a lot so I can't say if it was in there or not).
The numpad enter popup was incredibly useful for a variety of different things, to look up most effective ranges for your guns, special things like equipment on the tank, etc. One key feature was a basic penetration chart against "normal" armour at 0°, 30° and 60°, which often served as a good indicator if that gun had a good chance to penetrate that tank or not. It also featured rough armour thickness and angles of the tank. Granted it wasn't too accurate, but having a chart say 70mm rounded is better than nothing.
The limited amount of time I played CM:SF (quite frankly, I hated it, not because of the mechanics but because of the horrible scenario... I just dislike modern settings, let alone asymmetrical warfare) I always missed that key, and I personally find these different categories complete unusable and nonsensical. Is a 75mm considered a medium or a large calibre? If a 50mm is considered a medium calibre and a 88mm a large calibre... is a 75mm a large calibre? What about the M1 76mm or the 17 pounder? If the 17 pounder is considered a large calibre and the 75mm a medium calibre... is the KwK42 a medium calibre? God, that system is just complete unusable IMO and confuses me more than I could use it as a guide. It didn't take any special things into account but then again, I don't think anybody would want that.
I simply want a rough indicator at what kind of armour my tank has and what kind of capabilities it's gun has... heck, even ToW does a way better job in this regard than CM:BN. Granted, I know quite enough about armour, guns and the physics behind armour penetration but CM:BB is the reason that got me into this kind of stuff. If it wouldn't have been for CM:BB I never would've started to read up on this stuff, buy books and study reports. I hate the very thought that THE one single feature that opened this whole world to me... is gone.
Yes, I do associate a LOT with this one single feature.