The Charge action has a few problems with it, and the published errata take the wrong approach. I’ll give the bottom line of how to fix it first, and then explain why it should be fixed this way.
The four changes that are actually needed to fix the Charge action are:
1. Restore Overrun to the way it is written in the PHB.
2. Change the Charge action so that you CAN charge through allies as with any other movement (as it was in 3.0).
3. Change Ride-By Attack so that you may ignore the normal Charge rule that forces you to go to the closest space to your opponent, while preserving the "straight-line" rule and the restricted terrain rule.
4. Specifically allow a "Readied" Charge action, but make it clear that the single move action allowed with that Charge would be the total movement allowed in the round.
Here is why:
For items (1) and (2) above: As published in the 3.5 PHB, an enemy could avoid your charge if you used the Overrun action, but an ally could not. Errata were published to "fix" this by disallowing the Overrun action when charging.
This ruling severely handicaps Charge as a legitimate tactic. The Trample feat becomes useless if you cannot overrun as part of a Charge. On the other hand, if you could Overrun as part of a Charge, then you have the problem of why can't allies move when opponents can? So either Overrun is allowed or Trample is disallowed as a feat. The obvious, simpler, more consistent choice is to allow Overrun as written.
For item (3) above: Ride-By Attack is also nearly impossible. The Ride-By Attack feat needs to allow one to actually ride-by your opponent instead of charging up to the nearest square, which would, in most cases, prevent the Ride-By Attack from happening. Either the Ride-By Attack feat needs to be eliminated or slightly changed to specifically allow one to actually ride-by the opponent charged. The latter is the more obvious, simpler, more consistent choice.
For item (4) above: You do not seem to be able to Ready a Charge any more (except with a bit of a creative interpretation). This is too severe a restriction on a legitimate tactic form 3.0e. The easiest fix to this to avoid the 3.0 abuse of this tactic is to simply require that a Readied Charge uses up all movement for the round
It may be that some feel that mounted charges were too effective and thus unbalancing, but several years of experience with a paladin who always has his flying mount (a small paladin with a half-celestial war dog) makes it clear that such a character still does not do better in combat than a straight fighter or a barbarian. In certain situations he does better in melee, in others he does worse. Strictly following the published errata (no Overrrun) together with the "closest space" rule makes this type of character nowhere near as good in melee as any other PC designed for melee.
