There's nothing particularly unintuitive about how Ready works in 4e. If you have the initiative, you can anticipate your opponents actions and be ready to react to them decisively. It's a little /less/ potent than in was in 3e, because it no longer interrupts the triggering action. If it did, the tactic of readying triggered by an ally's buff wouldn't work - or wouldn't work as easily, you'd have to set the trigger to something else the ally is doing. But, readied actions would then be more potent when used against /enemies/.
So be careful with a house rule meant to 'power down' one tactic, when it may 'power up' other, more significant ones.
Edit: BTW, note that the tactic has a minor downside. You re-set your initiative downward whether the warlord hits or not. When he misses, you've delayed your own attack for no benefit. If, for some reason, he can't attack - if the target gets away, the warlord is dropped or stunned (or you are) or whatever. So there's a bit of a risk, and, generally, you take risks to earn greater rewards.
It's about a coordinated effort. If the two characters are 'working together like a well oiled machine' they'll use the ready option (possibly sacrificing an action along the way to do it, depending on where they each are in the initiative order relative to the enemy). If they're more just fighting on the same side, but being oportunisitic rather than planning things, they'll use the action point - and the higher-initiativec character won't have to sacrifice the advantage of going earlier in the round to possibly eke out a better attack chance on an extra attack.
Both styles are valid - and viable.