See, this is now a tough question. Expertise and Paragon/Robust Defenses and one untyped Epic NAD feat at Epic to the lowest NAD and then ban the rest is the answer that easily fixed most of the math issues.
But now you have stuff like Light Blade Expertise, whose secondary benefit is completely worth it even without the Expertise part. Ditto Spear Expertise. Heavy Blade Expertise? Not so much.
What I would do:
+1 to attacks at 5/15/25. If they voluntarily take an Essentials Expertise Feat for the secondary benefit, this has the side-benefit that those feats give +hit at 11/21 instead (though they could exploit this via retraining at said levels, but eh). Make sure you allow Expertise to apply to any racial or non-Weapon/Implement keyword that scales at +2/4/6 (should be 3/6/9 with Expertise, think Dragonbreath).
Improved Defenses for free at level 9. If they take any of the new Superior Feats this'll be overwritten, but that is fine, as they'll still get an additional +1 to that NAD and those feats have serious side benefits.
And I would still give out an Epic NAD Feat at 21 to each character's lowest NAD, then ban the rest.
Some people consider Melee Training for Melee Characters who have no in-class option to get a decent MBA to be a tax. I don't personally agree with that, but YMMV.