a) DC 15 + BAB means that the DC versus a powerful and skilled fighter is obviously higher. Whether its as high as you would like is a somewhat different matter.
True. We have set the bar pretty high. We wanna keep it hard to avoid the AoO, but not so hard as CMD as DC vs a skill check. (CMD is Touch AC +BAB +STR +Size mod)
First, let me clarify, does the +6 dodge bonus to AC while Tumbling only apply to AoO (as was applied in your earlier post) or does it apply against all attacks? The former I claim is weak. The later I would agree is quite powerful indeed.
Only to AoO while tumbling.
decreasing the odds of tumble succeeding while increasing the odds that the ogre misses amounts to no real net change.
I would however say that with 24 acrobatics, you'd probably ALSO get 95% immunity or better to most peer level foes applying my rule of 15 + BAB.
15 + BAB is a very good rule. It's sound and simple. We could use this rule, but we wanna adjust the numbers on this other one to make it work, we think it will make the results more umpredictable with all the different Attack & AC modifiers that can come up during combat.
Your version means your 8th level acrobat even maximized with Mobility only has an AC around 33 and probably gets hit by even a 10th level non-optimized fighter (or a dragon, or an equivalent outsider) nearly half the time - which is why I said that it's no longer worth risking the AoO
Yep, I made a mistake whe I said it would always be worth tumbling, there will be times when the risk of getting hit will be too high and it will probably be better not to tumble.
I think we understand each other, you want to have situations where you'll have 0% chance of failure in tumble, and I want to make sure AoO will not be easily avoided, but I also wanna be able to benefit from tumble at some level, even when the odds aren't great. Both systems are good options to replace the basic 3.5 DC15 and the Pathfinder CMD DC, but ours still needs some tweaking to get where we want.
It's also good to notice that, in this system, the enemy spends his AoO, even if the tumble is successfull, but at least he got to take a swing at you.
BTW, this question came up in another forum that got me thinking:
Q: If you tumble to avoid AoO, does the enemy spends his AoO?
A: No
This makes no sense. Picture this, a Rogue decides to tumble through a Large Ogre threatened area.
The Rogue moves up to the start of the Ogre's threatened area and start to roll or whatever at half speed (for some reason, moving at half speed makes you harder to hit).
The Ogre sees the Rogue rolling by him and thinks: "Damn, he's rolling, I can't take a swing at him!"
If the Rogue succeeds the check, has to move through all threatened squares at half speed.
This is how it should be:
The Rogue moves up to the start of the Ogre's threatened area and says "Yo! DM, I'm gonna tumble past the Ogre, do you wanna take a swing at me?" and he shows how he wants to move, but doesn't roll the tumble check yet.
The Ogre sees the Rogue rolling by him and thinks: "Damn, he's rolling, I'm not sure if I'm gonna hit that. Maybe I should let him go and wait for that chubby Cleric instead, when he tries to pass."
IF the Ogre chooses to not attack the Rogue, he forces him to spend more of his movement by walking the whole way at half speed, and saves his AoO for someone else.
If the Ogre does choose to attack the Rogue, he chooses in which square the attack will take place, and then the rogue rolls his tumble.
If the tumble succeeds, the Ogre's attack misses and the rogue can just walk the rest of the way, since the Ogre won't be able to attack him again for the same movement, just like anyone else that initialy just tries to pass thorugh the Ogre.
If the tumble fails, the Ogre's attack may hit the Rogue or not. Either way the Rogue can now move the rest of the way normaly, if he didn't die or got knocked prone.
In the end, the Ogre can choose to take a swing at the tumbler or not, but he won't know if the tumble was successfull or not until after he chooses.
This makes more sense, except for the part where moving at half speed makes you harder to hit, that part still doesn't.