Putting forth the Barbarian/Oracle "cheat" to my children, they responded that don't think they would take the level in oracle on anything like a regular basis for their Barbarian characters. There are other workarounds to fatigue and its rarely that big an issue anyway in actual play (especially by 9th level, which the the first time you could do it). Most of the time, when the barbarian finishes raging, the fight is over. The few times it was an issue in fight, in our current game, the divine channeler was able to remove the fatigue with a touch. The loss of speed also dismays my oldest daughter who apparently is partial to the fast movement of a barbarian (though she normally plays spellcasters). So I doubt this is going to be much of an issue for our game.
I quite agree - it's not an issue in ours either. It is, however, the "go to min/max build" for entering and leaving rage to use powers that work once per rage, etc. If ou play with gamers building characters rather than optimised stat blocks (and it sounds like you do), I suspect it is rarely or never seen.