Actually the +1 damage and -1 to hit is almost perfectly identical vs AC 20.
Let's use a longsword (+3) and give STR of 18 (+4) and WIS of 12 (+1). In reality, you'd probably have a better WIS if you're a STR-Pal, making this comparison a bit unrealistic. But just for the sake comparing ...
DPR:
Holy Strike [7 x 9.5] + 13(crit) = 79.5; 79.5/20=3.975
Valiant Strike [8 x 8.5] + 12(crit) = 80; 80/20=4.000
Now let's make it a WIS of +2
Holy Strike [7 x 10.5] + 14(crit) = 87.5; 86.5/20=4.375
Now WIS of +3
Holy Strike [7 x 11.5] + 15(crit) = 95.5; 95.5/20= 4.775
Let's make the comparison a little more realistic...you're picking the ideal situation for you, which is unlikely to hold at even 1st level...and you're comparing apples and oranges, not what I was talking about, which is the benefit of a +1 to damage vs a -1 to hit. Not what the benefit of a +1 to hit is compared with a moving target dependent on stats.
Let's use a bastard sword (+3)(or WF, doesn't really matter which one as crits adjust automatically) and look at AC 20 and power attack, with a Holy Strike at +2 extra damage.
DPR:
Holy Strike (7*11.5) + 17(crit) = 97.5; 97.5/20 = 4.875
Holy Strike (5*13.5)(PA) + 19(crit) = 86.5; 86.5/20 = 4.325