I found a lovely fix, suggested by Keterys:
[sblock]Instead of to-hit being based on the stat the power is associated with (such as Dex vs. AC), to-hit is measured thusly:
5 + 1/2 level + weapon proficiency.
+1 at levels 5/11/15/21/25.
Ban Expertise feats.
Damage is still based on the primary stat associated with the power (thus a Cha-based power is going to do +cha damage).
Benefits: Addresses MAD of Starlocks, and allows split-primary classes (Cleric, Paladin, Ranger) to go with any power they so choose. Allows for any multi-class, as you're not locked in to ability scores. Less of a rush to maximize primary stat at the expense of other ability scores. Wider array of likely race/class combos, instead of a limited race/class combo to maximize the primary stat. Removes the feat tax of Melee Training.
Yes, this means that a str-based paladin and a wizard wielding the same weapon have the same chance of hitting with a melee basic attack. That's okay with me. The Str-based paladin still has awesome melee powers and does more damage, and isn't going to get his ass handed to him in melee.
Yes, this will likely irritate those who like to play with ability scores and like being good at one thing while being poor at another. I find it simple, and definitely cuts down on needing system mastery and a dependency on a high primary ability score.
And yes, it may reinforce the feeling that "all the classes are the same" and "Uber balance in the face of fun".
But my issues with the system go far beyond the MADness of the Paladin/starlock. In fact, the MAD classes aren't the biggest issue on my radar, as to why I like this method so much. [/sblock]