Booming Blade actually has a lot of interesting quirks about it.
-snip-
Q4) Does Weapon Focus add to the punishment damage?
Yes. This is a power with the Weapon keyword, and even tho there is no [W] component, this is still a damage roll using the weapon, which is by definition happening with the Weapon keyword.
Nope. The Weapon keyword means that all the damage is done by the weapon. Every aspect of the power is altered by the weapon. If it were not the case, and that [W] was what defined weapon damage, than swordmage implement powers with [W] damage would be altered by Weapon Focus, and they are not. Therefore [W] is not the defined trait of how a weapon deals damage.
Griogre - that's a perfectly reasonable house rule to take (though it has far ranging ripples you should factor in and adjust powers for), though I'll note you should clearly spell it out for figuring out all of the other powers that have secondary damage rolls, multiple damage rolls, aura damage rolls, entering and starting turn in zones, etc. Or perhaps you're just house ruling a couple powers, like hellish rebuke and dire radiance, nerfing warlocks slightly (which I don't think is a good idea).
It is not, however, the RAW. There is no ambiguity on this issue.
Thus the plural attack rolls and damage rolls is referring to the plural Magic weapons and implements. This pattern continues through much of the Enhancement text but I didn't want to quote more than a couple of paragraphs. That is the basis for me believing that you apply each bonus from magic weapons and implements *once* to each attack.PH said:For items that give an enhancement bonus, this entry specifies what that bonus applies to: AC, other defenses, or attack rolls and damage rolls.
Magic weapons and implements grant their enhancement bonus to attack rolls and damage rolls only when you use powers delivered through the weapon or the implement (or directly from the weapon or the implement, for items that have attack powers).
Note that the sentence is referring to what each (singular) bonus applies to.I believe that the plural to “rolls” refers to the different magic items and different implements referred at the start of the sentence. I believe this because the first two paragraphs are all written with plurals. I bolded the plurals below.
There's no distinction made as to which attack rolls should be affected and which should not - the text speaks of attack rolls in general. The text also points out that the power states if it is performed via a weapon or implement. The section on how to read a power (p. 54) and specifically the bit about keywords on the opposite page explain that the weapon/implement keywords "identify items used with the power.", and mentions again that the enhancement bonus (and proficiency bonus, for a weapon) applies to attack rolls "when you use a power that has the associated keyword". Note also that the concept of "base attack bonus" as explained on p. 274 is per-power (which you should calculate for all powers including basic attacks) and includes "an enhancement bonus (usually from a magic weapon or implement)"! The attack roll in general is explained to consist simply of "the power's" base attack bonus, situational modifiers (combat advantage etc), and bonuses and penalties from powers affecting you.PH said:For items that give an enhancement bonus, this entry specifies what that bonus applies to: AC, other defenses, or attack rolls and damage rolls.
Magic weapons and implements grant their enhancement bonus to attack rolls and damage rolls only when you use powers delivered through the weapon or the implement (or directly from the weapon or the implement, for items that have attack powers).
Q4) Does Weapon Focus add to the punishment damage?
Yes. This is a power with the Weapon keyword, and even tho there is no [W] component, this is still a damage roll using the weapon, which is by definition happening with the Weapon keyword.
Q5) What about enhancement bonuses?
Yes. Again, power with Weapon keyword gets enhancement bonuses when a weapon is used with it. As well, you get the critical bonus of the magic weapon, and if the power has a Weapon keyword, you get the high crit property of a weapon if you're using it.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.