with paladin level 20 and divine Shield you will qualify for epic Divine Shield, which would add some level of Concealment to your build.
Also, for a WeaponMaster i would take Falchion over Greatsword for the better crit chance, and switch ImpCrittical for PowerCrittical, you can craft keen on your blade later i think.
Also i would go for P21, F12, And WM 7 to get EpicWeaponFocus, EpicWeaponSpecialization (for a bonus of 6+BAB/5 if the forum info is still correct), EpicProwes, ExpertTactition, Toughness, SteadfastDetermination (must have on RoT), and NaturalArmor I - III or EpicHeavyArmorSpezialisation
With a belt of Tempus you could also get Practiced Spellcaster
Since you have used just 3 from your 4 max classes you also could get Cleric on Level 40 instead of paladin level 21 for 2 more feats
As always just my 2 cents
removed wrong NaturalArmor Calculation