Note - My crit = hit assumption is the basis for the normal hit rules being excepted in the case of Holy Ardor. Other rules that apply to crits still apply.
This is the problem with your argument in the nutshell tho. You've assumed that 'score a critical hit' is a hit, and you've used that as the basis of your argument that scoring a critical hit is a hit.
That's a blatantly circular argument.
Anyways... on to a different argument.
Daggervenger vs Ardorvenger.
Both are using Bloodiron weapons, a Execution Axe in the case of the Ardorvenger. Both will seek CA, and the Daggervenger will only use his Sneak Attack damage on his critical to maximise his effectiveness. Both will start with 18 Wisdom.
At level 11: 18 Wisdom becomes 21 Wisdom, with Expertise, and +3 weapon, and Combat advantage, =5+5+2+3+2 = +17 base to hit, +20 with a dagger, +19 with Execution Axe.
Iron Gorgon is a level 11 monster with 25 AC. Dagger needs 5 or better to hit, Exec needs 6.
So, out of 400 outcomes, Daggervenger will critical on 111 of them, and will otherwise hit with 273 of them.
On a hit, this Daggervenger will deal 1d4+10 damage (12.5 average), and on a crit, will deal 32+2X(3d10)+1d10 (32+7d10 | 70.5) damage. Not bad.
The Ardorvenger will crit with 53, and otherwise hit with 322 outcomes.
On a hit, the Ardorvenger will deal (1d10+2)+10 damage (brutal 2)[17,5], and will deal on a crit: 22+2X(3d10)+1d10+1d10+2) (24+8d10 | 68) damage.
Now, let's do a comparison.
Ardorvenger is worse for these attacks if:
[68(53)+322(17.5)]/400 < [70.5(111)+12.5(273)]/400
Which turns out to 9239 < 11238. So, yes, Ardorvenger does less damage per round at level 11.
-However-
This changes at level 16.
Bearing in mind that the bonuses to hit are constant between the roles, and the bonuses to damage from sources are constant, the big difference is in the size of the crits.
See, at that point, every time you crit you get a free attack. Had this been applied above, you'd have 9239*453/400 instead of 9239 in there. That would have made it 10139.8, instead of as close as it is now.
So while Ardor is less damaging over time, it is -certainly- not a bad damaging PP for an avenger at paragon level. You're certainly not 'sucking' at those levels. Then, when you get to epic, you take Eternal Defender. This changes the math -considerably- on the side of the Ardorvenger. While Daggermaster could theoreticly be dealing 2d6 with his weapon at-wills, the Eternal Ardorvenger is dealing... well instead of a 1d12 weapon with brutal 2, it's now a 2d6 weapon with brutal 2... so you're now looking at replacing 1d10+2 with 4d4+8.
Once you get to Epic, Ardorvenger is a -clear- winner over a Daggervenger.
Of course, this is only with at-wills. Once your [W] gets higher than 1, things change -dramaticly- as well.
This also doesn't take into account the possibility of a Rending Weapon, which gives you -more- attacks with criticals, but is only on an Axe. In this case, you'd be reducing the amount per critical for the Ardorvenger by 3d10+6, or 21.5/outcome, or 1182.5 total, for a total value of 9239, or 8056.5, or 20.14125 DPA.
However... you end up with higher effective DPR because every crit gives you a free attack. So, in 55/400 cases, you re-add in the DPR. And every time -that- crits, you again add in the DPR.
So...
d = 20.14125 + 55d/400
400d = 8056.5 + 55d
345d = 8056.5
d = 23.3521...
400d= 9340.
So a Rending Axe is better DPR for an Ardorvenger, and with the capacity to make -two- free attacks at level 16, and at epic being a 2d4+4 (effective) weapon...
This could actually get to be quite sick.
Oh yeah, Irresistable Ardor and Battle Rapture are not terrible powers as well. Unlike a Daggermaster's powers which are... not exactly great for you.