The problem with saying "Oh, just go to Swoops and compare times!" as an absolute reference to pet damage is that Swoops has extraordinarily high physical resist - of COURSE the Greater Dragon is going to be outdamaged there, excepting the occasional Fire Breath. It would be like saying "Greater dragons clearly outdamage Bake/Rune Beetle combos... just see how fast a[Instert energy resist 90 monster] go down to Greater Dragons, comparatively!"
Also, I believe the max weapon speed for wrestling is reached at or before 125 - when at full stamina, a Rune Beetle with 170 dex isn't hitting any faster than a Greater dragon at its 125 max.
To compare pet damage, I've used the stratics combat formulas.
Let's start with something as basic as possible - Melee damage.
Greater Dragons:
For melee damage, the damage range depends on your dragon's stats - a weaker one with lowish tactics will be hitting for ~95-100 at the low end, 130-135 at the high end. A high strength, high tactics one will be hitting for 105-110 at the low end, 145-150 at the high end (with 110-151 as the maximum melee damage)
A Bake Kitsune's stat spread basically makes around 1 point of damage difference - it does 44-64 damage at max stats.
A Rune Beetle near its max str will get 54-80 damage per swing.
Nightmares, with their potentially high strength, can be even more impressive - a max strength Nightmare does 62-86 damage in melee.
Based purely on raw damage, if every attack hit, a Bake/Rune Beetle matches the melee damage of almost any Greater dragon. A NM/RB combo actually outdamages it, in raw damage.
Of course, not all attacks will hit - its a comparison between wrestling skills, is it not?
Let's consider a target with 100 wrestling.
A Greater dragon with 125 wrestling will be hitting such a target ~62% of the time, while the Bake/RB will be hitting ~50% of the time. hit-weighted damage, then, is thus, assuming high-end but not max stats:
Greater Dragon: .62(105) to .62(145) = 65 - 90
Bake/RB: .5(98) to .5(144) = 49 - 72
NM/RB: .5(116) to .5(166) = 58 - 84
Note: Weighted damages are "per swing" rather than "per second" - to determine "per second" weighted damage, divide all damage numbers by the swing speed in seconds (I believe that's 1.25)
So, for purely melee damage, a greater dragon of decent stats will outdamage a bake/RB and NM/RB combo... right?
Well, potentially not.
Take a potential target, with roughly 70% resists across the board. A Rune Beetle's Corrupt Armor takes away roughly 20% on each resist (correct me if I'm wrong here), reducing all resists to roughly 50%.
Resist-weighted damage:
Greater Dragon: .3(65) to .3(90) = 19 - 27 = average of 23
Bake/RB: .3(49) to .3(72) = 14 - 21 = average of 17.5
Corrupted: .5(49) to .5(72) = 24 - 36 = average of 30
NM/RB: .3(58) to .3(84) = 17 - 25 = average of 21
Corrupted: .5(58) to .5(84) = 29 - 42 = average of 35.5
So what percentage of the time must the target be corrupted for the Bake/RB combo to outmelee a greater dragon? We'll use the averages for this.
The average corrupted damage times the percentage of corruption plus the average non-corrupted damage times the percentage not corrupted equals the GD average.
30t + 17.5(1-t) = 23
12.5t = 5.5
t = .44
Thus, to equal the melee damage output of a Greater dragon, a Bake/RB combo need to have the target's armor corrupted around 44% of the time.
For NM/RB
35.5t + 21(1-t) = 23
14.5t = 2
t = .14
A NM/RB combo needs the target corrupted merely 14% of the time for them to equal a GD's melee output.
Caveats:
1. Not all Resists are equal, nor are they targetted equally.
A Greater Dragon's melee attacks are 100% physical. A Rune Beetle's melee attacks are 20% physical, 70% energy, and 10% poison. A Bake Kitsune's attacks are 70% physical, 30% energy. A Nightmare's attacks are 40% physical, 40% fire, and 20% energy.
A very large majority of targets, barring PvP, have non-similar resists, instead usually having or two much higher than the average, with perhaps one or two resists much lower than the average.
Against something like a Greater Dragon, with on average a higher physical resist and fire resist than energy resist and poison resist, the Rune Beetle is going to really shine, as is its armor corrupt ability - a successful armor corrupt could nearly double a bake kitsune's melee damage output.
Against something with higher energy and lower physical resist (like cu sidhes), Greater Dragons are that much harder to equal.
2. Special abilities are frickin' hard to account for sometimes.
BKs, RBs, and GDs have bleed attacks, with GDs hitting slightly more but BK/RB combos getting more bleeding hits overall. Bleeding ignore resists, so armor corrupt doesn't affect 'em. i don't know if anyone knows their frequency, either. The Rune Beetle has a lethal poison attack, which can do anywhere from loads of damage over time (med to low poison resist, no magery or immunity) to relatively little (high to immunity poison resist and/or magery). I've never seen a frequency for this, either.
3. Stamina Loss isn't accounted for.
While GDs are hitting at the same speed as BK/RBs when at max stamina, stamina loss and/or dex-reducing curses might reduce a GD's swing speed where the same will still leave the BK/RBs hitting at max speed. This changes the weighted damage somewhat.
4. Extreme Dragon stats aren't acounted for.
I did these calculations for a dragon with 125 wrestling (about as high as one seems to get while still having decent resists and decent stats). A designed-for-meleeing-PvPers dragon with near-max hp, near-max str, near-max int, and near-max wrestling would change these numbers somewhat.
5. Magery and Fire Breath are not accounted for.
Initial, unsubtantiated thoughts indicated the BK/RB and NM/RB combos will outdamage a GD's magery by a significant margin, especially when Armor Corrupt is taken into account. Fire Breath is also a very substantial amount of damage.