To break down the current roles of the shrike. It has a few main uses. Some of which most people can, a few an extremely limited amount can do.
A.) Escort air/Kill enemy air. : Mainly bombers now in classic. A decent amount of people playing can do this to varying degrees. Most lack awareness to make it fully effective. Most people can also shoot down enemy bombers when not escorted, and have varying degrees of shrike vs shrike skill. Most however don't have awareness.
B.) Cap : All people can use the shrike for this. Shrike capping in terms of grabbing the flag and getting back in is all but obsolete now. Stoppable by any forms of defense. It's main use for capping is transportation a few hundred meters away from the flag for light capping. Or directly grabbing in medium. The only time you see someone getting back into a shrike successfully by himself is if the defense is utterly horrible, or has been dominated by the offense.
C.) Midfield : Extremely few people can do this part well enough to have any impact on a high level match. By extremely few I mean 6 or less people playing the game. That's probably being too generous as it is. Midfield as defined as having a visible effect on enemy offense and enemy chasers by taking them out consistantly with rams. This requires a great deal of awareness to be effective on a consistant basis. It also requires great aim due to the high speeds of classic. (Note: to do consistantly). The effect it can have can be something of an advantage but certainly not a game winner in its own right. It can stop alot of caps/HO that would have gotten through with ease however, making it of vital importance if your team has someone who can do it correctly. But as said, extremely few people in the game can make in impact while being dedicated midfield.
D.) Combo of the above : The people who can midfield well can most always escort other air well. They also tend to double as cappers in key grab situations or if the flag is simply open. As it stands, most people can do a bit of A.) and B.), and hardly any can do C.). Regardless, its vital to the game and its variety, and should definetly make an appearance in T3.