I think it's not a terribly useful feat for the most part - in any games I've been in, reach wepaons and mounted charges have been few and far between.
Also, keeping it in the spirit of 3E rules, I really don't think the feat should allow you to double all the damage from your Strength bonus on any given blow - in the case of a charge with a lance, it should give you double your strength bonus (from the feat) + your normal strength bonus (for using a lance), for triple damage - quadruple damage on a critical.
Also, keeping it in the spirit of 3E rules, I really don't think the feat should allow you to double all the damage from your Strength bonus on any given blow - in the case of a charge with a lance, it should give you double your strength bonus (from the feat) + your normal strength bonus (for using a lance), for triple damage - quadruple damage on a critical.