Wulf,
I'm at toss up. I was happy with the Pathfinder solution to iterative attacks (Vital Strike and Imp. Vital Strike) which essentially fixes your attacks at 11th level and beyond to 0,-5 with a damage boost (1 extra die of damage or two extra dice of damage).
Flat damage boosts don't really replace iterative attacks. They can't, because a flat damage boost has no way of knowing how many damage dice you might have been adding.
Let's look at SWSE for example, that gives a flat damage boost of 1/2 your level instead of iterative attacks.
If your attack has a fairly low vanilla damage rating-- say a plain sword with an average of 9.5 damage-- then a +10 damage bonus at +20 BAB works out just fine.
But if your attack is a +3 holy flaming longsword, and you happen to be sneak attacking for +7d6, well then a flat +10 damage isn't going to come close to replacing the lost iterative attacks. (You'd average 1d8+2d6+1d6+7d6 = ~40 damage, plus STR.)
Vital Strike and Improved Vital Strike work the same way. They only multiply the base weapon's damage-- no bonuses for STR, magical effects, sneak attack, successful crits, etc.
If you're using a weapon that does 1d8 base damage, then Vital Strike takes you from 1d8/1d8/1d8 at 0/-5/-10 to 2d8/2d8 at 0/-5.
I like that you retain the option of additional iterative attacks for the "edge" opponents with the Pathfinder solution.
Well of course you do! Who
wouldn't like to choose the best possible expectation at all times?
I'm wary of Spreadsheet Warriors who keep a tally of exactly when they are better off using Attack Mode A or Attack Mode B.
I'm also curious if you have modeled the PF solution versus yours and how it turns out from a hit perspective and from a damage perspective.
Just eyeballing it I can tell you that can't replace an unknown amount of damage (flaming? high STR? sneak attack?) with a known amount of damage (weapon average damage) and expect it to "work out."
Basically, given the choice, you will
always use Vital Strike if the damage expectation exceeds the expectation on your third attack.
If Vital Strike adds 9 damage (on average, considering 1d8 base weapon that yields a 2d8 boost) then you will use Vital Strike anytime that:
9 > (3rd attack probability)*(3rd attack average damage).
If your third attack has a 5% chance of hitting (nat 20), you'd need to be averaging 180 damage per attack to equal Vital Strike. (Not likely...)
Conversely if your 3rd attack hits 50% of the time, you'd only need to be averaging 18 damage-- trivial for most fighters and rogues.
You can do the math in reverse. If you know that your holy flaming longsword sneak attack averages 40 damage, then you know you want to use it anytime your chance to hit on your third attack exceeds 9/40, or 22.5% (ie, you hit on a natural 16 or better).
If you need a natural 17 or better, go with Vital Strike.
Speaking, admittedly, as a lazy designer who is just eye-balling it, I conclude that Vital Strike is lazy design and Jason just eye-balled it.
P.S. Get cracking on Trailblazer.
Dude, this
IS cracking on Trailblazer.