Use the suggested moderate DCs from the most recent skill update
We have three classes of characters who grab: The Normal Character, The Weaponmaster Brawler, and the Red Scales Assassin.
The normal character grabs to satisfy rare tactical objectives of capturing an enemy without knocking them unconscious. It would be reasonable to assume that the rest of the party would pile on and that this would represent the conclusion of the combat if the grab can be held for some duration.
The Brawler grabs to lock a single enemy down. She will use this every fight and will serve as second defender. This, therefore, should be a good tactic for her to use. In the best of all possible worlds, a brawler should (by default) start her turn with an enemy grabbed roughly to-hit % of the time.
The Assassin can attack through a sustain standard on his grab. It would be nice if that had approximately equal odds to his attack hitting.
Powers of especial note are: Garrote Strangle (Executioner Assassin), Grappling Strike (Weaponmaster Fighter), Grab (Default. STR v. REF, no modifiers. Immobilizes), Net Snare (Foamgather Warrior Feat)
Rough target DC: to-hit chance.
Fighter:
- Heroic: Assume 18 base STR (+4) , +2 brawler style, +2 class, +10 base = 18, 23
- Paragon: no special +fort PP. Str 21 at 11, 22 at 16, +3, +4 items. = 28, 32
- Epic: +2 to str from ED, Str 26 at 22, 28 at 30, +5, +6 items = 37, 44
Assassin
- Heroic: Assume 14 base STR (as per guide, +2), +1 class, +10 base = 13, 18
- Paragon: guild exectuioner, Str 17 at 11, 18 at 16 = 22, 27
- Epic: +2 Str from ED, 22 at 22, 24 at 30 = 33, 39
For purposes of this analysis, we'll assume the average grabber follows the assassin fort progression and that no-one ever tries to escape via reflex (fighter has a feat that prevents it, assassin just laughs.)
Average of first 5 standard monsters at each level
Monster untrained athletics at 1,6,12,16,22,30:
- 1: +1, -1, +3, +3, +0 = +1.2
- 6: +6, +6, +8, +2, +7 = +5.8
- 12: +12, +11, +11, +12, +11 = +11.4
- 16: +15, +15, +15, +9 = +13.5
- 22: +20, +18, +13 = +17
- 30: +24 (MM3) = +24 (not enough data)
Brawler Fort at 1,6,12,16,22,30: 18, 23, 28, 32, 37, 44
Assassin Fort @ 1,6,12,16,22,30: 13, 18, 22, 27, 33, 39
Mob Athletics @ 1,6,12,16,22,30: +1, +6, 11, 14, 17, 24
%Odds of escaping fighter: .... 20, 20, 20, 15, 05, 05
%Odds of escaping assassin: ... 45, 45, 50, 40, 25, 30
Moderate DC @ . 1,6,12,16,22,30: 12, 15, 20, 22, 27, 32
%odds of escaping moderate dc: . 50, 55, 55, 60, 50, 60
While moderate DC isn't perfect, it does represent roughly even odds on both sides. Feats and items that improve defences for purposes of sustaining a grab modify the DC instead. It keeps the odds roughly consistent across levels, and means that a absurd fortitude pump isn't necessary to spec as a grabber. So long as the grabber carries a way to prevent teleportation, the modification to grab rules means that targets will have even odds of being grabbed and will generally waste their move actions trying to escape, maintaining the efficacy of the grab as action-denial.