While I don't doubt that there either is or will be a program or plug-in that can/will do this, there's simply no logical reason for it. Every song has a different overall EQ curve based on the parts within the arrangement. Rock mixes tend to have a far more pronounced midrange curve than an R&B track, which often has an absolute glut of midrange information. Hip hop tracks have a pronounced bottom. Indie tracks often have a pronounced lower midrange.
A track packed with a singer, guitars, B3, and drums all carrying fundamentals in the middle octaves is going to have a far different EQ curve than a track with programmed percussion, a high pitched string pad, a beefy kik a snare, and a robust bass leaving a major hole in the middle filed twice a measure by a snare drum.
Further, in my experience, every track, every mix, has it's own unique and naturally occurring EQ curve. Yes, we EQ the individual parts to make them fit together, but it's the sum of those parts that makes the curve. Using a program to change the overall curve of the stereo mix doesn't make a whole lot of sense when you think about it. Take a rock track that has an obviously pronounced midrange because of the stacking of instruments playing within that range, altering that curve will merely have the effect of changing the overall balances within the mix. Trying to give an R&B track more midrange is going to change the balance of the few instruments that actually fill the middle.
It seems to me you're looking for a quick fix for what amounts to nothing more than arrangement and balance choices. From Zen and the Art of Mixing:
"The more buildup there is in a certain frequency range, the more difficult your job is as a mixer. For instance, if a production has a Farfisa organ, multiple guitars, and piano all playing in the same narrow middle range, you’re going to have a considerably harder time fitting them all into that space than if they’re spread out across the full spectrum. If there are two basses, a djun-djun, a low tom beat, and a cello, you’re going to have a hell of a time carving out enough space in the low end to avoid a muddy, undefined mess in the bottom of your mix. And if there’s too much high-frequency information in the mix, the mixer and subsequently the listener are going to find themselves exhausted in short order.
The power that frequency has over the listener should not be underestimated. How you use frequency information in a mix can have a direct bearing on how that mix makes the listener feel. How your parts fill the frequency spectrum in an arrangement can be just as important as how they fill their role musically. Keep this in mind as you mix."
So how are you going to fix a dark track caused by excessive low end information or a bright track caused by excessive high end information contained with in the arrangement intself? Really, the only way to deal with these sorts of imbalances is with the mute button. Not by scooping out the fundamental frequencies which are caused naturally by your own arrangement choices.
My recommendation is to not compare one track to another. Every track has it's own unique sonic fingerprint. If you're not happy with that fingerprint, then this is a balance and arrangement issue. Not an EQ issue.
Enjoy,
Mixerman