James McMurray said:
Do you mean to say that ignoring armor and natural armor is only worth a +4 bonus?
What i believe he means is this : Per RAW, Brilliant Energy does not ignore Natural Armor. If you made Brilliant Energy = Touch Attack, it would. The problem I see with this is that it would become a
much more useful enchantment in the hands of the PC's. To compare it against some opponents that a character with access to a +5 weapon might face (using character wealth by lvl - Table 5-1 pg. 135 in DMG, and assuming that the character uses ~1/3 of his wealth on the weapon - lvl 14):
Adult Red Dragon - CR 15 - AC 29 (-2 size, +21 narural
Bril.Enrgy AC 29
Touch AC 8 <- Wins
Beholder - CR 13 - AC 26 (-1 size, +2 Dex, +15 Natural)
BE AC 26
Touch AC 11 <- Wins
Nalfeshnee - CR 14 - AC 27 (-2 size, +1 Dex, +18 Natural)
BE AC 27
Touch AC 9 <-Wins
Lvl 14 NPC fighter - CR 14 - AC 27 (+1 Dex, +10armor , +3 shield, +2natural, +1 deflection)
BE AC - 14
Touch AC - 12 <- Wins, but the difference is small.
Storm Giant - CR 13 - AC 27 (-2 size, +2 Dex, +5 Breastplate, +12 natural)
BE AC 22
Touch AC 10 <-wins
What i'm really trying to say with all this is that BE is a great if your GM puts lots of "Humanoid in Armor" types as encounters, but vs the great majority of the monsters in the MM, it simply isnt worth it. However, that BBEG rogue w/ improved invis + BE dagger is going to give the PC fighter nightmares for years. YMMV by campaign/ DM choice of monsters.
To aswer the quote, no, a enhancement that made all attacks touch attacks would be an epic-level enchantment, definitely much more than +4.