Ok lets get into specifics now and blanket the entire discussion while we hide behind such awsome comments as "Bad healers arnt good". Obviously healers in greens healing dps in greens will not win a bg, that's nothing about what was being discussed at all.
How is that specific? Generally, teamwork is more important than class/roll distribution in randoms. Sure once in a while you'll get some really odd comp like 9 DKs and a warlock or something, but like you said - just because it has happened doesn't mean it always happens.
Normalizing bg rosters will only make queue times longer - they will not guarantee a fair or even fun fight. It is up to players to get into a bg, look around and try to use what they are given to the best of their ability in order to pull out a win.
No matter what, there will be disparities in random bgs. Even if they put an equal number of healers on each team, there will still be gear and skill discrepancies that will cut into peoples' fun and make games seem "unfair". Basically, if you can't play as a team it does not matter how many healers you have or whether you have a tank with you or not.
That is what I was saying, and I think it ties into the "discussion" here pretty directly.