Having myself played 6th edition, 7th edition and 9th Age, I would recommend 9th Age. It's by far the best balanced version of Warhammer, heck, I'd say *the* best. Also, with update 2.0, the classical 6th/7th edition Empire playstyle of parent-unit/detachment combined arms is making a comeback in viability.
They say 6th/7th ed was the golden age of static CR, but then, once the enemy brought enough killing power to go over a threshold where he could negate the CR provided by your three ranks and your flanking, you broke. 8th edition at least brought Steadfast to give blocks some staying power against non-blocks, buying you time.
T9A 2.0 will make detachments in support range fight (and shoot) in an extra rank, which should make offensive units particularly useful as flanking detachments. Parent-detachment combined charges add together their rank bonuses too, and each standard gives +1 CR, and bonus VPs for captured standards is no more. So while T9A 2.0 may not bring back detachment goodness to the same relative prominence of static CR as was had in 6th/7th, it also creates a force multiplier to the killing power of the units involved. I think that T9A 2.0 will actually be the first edition of Warhammer where halberdiers are clearly the preferred unit type for flanker detachments, and there's just something very right about that