You’ve still potentially got that with the subsequent attacks doing 1d10+n damage, which with low hit point enemies still has the possibility of putting them down. But the serious momentum (which gives the bonus to hit and damage multiplication) is gone with the initial attack, as far as I’m concerned.
I’ve treated Cleaves as being made with all the same bonuses as the original attack, which made our ranged backstab thief very happy as he was able to shoot a shaman through his guards.
That discourages realistic tactics, like disengaging to re-charge. The fact that you have a Cleave is enough, no need to heap on extra benefits.
In big scale battle the rules are different. I really only see disingaging to charge again in big scale. I don’t see the benefit of it in small scale unless you are a dedicated charger. Even then smart people will know what you are doing and set against a charge.