Nice idea man! I never considered using items in competitive matches, until now.
Me and a friend did some playing/testing, your idea seems to work well for the most part. I managed to do record a couple tidbits, which may be useful to you...
All the following was done on training mode against a mario (lvl 9) set to stop on final destination, while he is in the middle of the stage. (We used the fact that he lands on the same spot after respawn as the center.) Keep in mind cpu's don't use DI.
I/we were ganon, we just rotated now and then.
dmg = damage
~ = approximately
> = less than (ex 60 > 50)
Most K.O% aren't exact. All dmg values should be exact.
correct grammar isn't used for the sake ease of recording, if you can read internet speak ('noobspeak') you shouldn't have trouble reading it.
All throws are fsmash throws.
ganon uncharged fsmash K.Os at 80% does 24 dmg
ganon uncharged fsmash K.Os at 105% does 19 dmg
Pokeball K.Os at 150% does 15 dmg
Barrel K.Os at 90% does 20 dmg
Crate K.Os at 90% 20 dmg
Capsule does not K.O at 100% 17 dmg
Rolling crate when fsmashed K.Os at >50% (Exact value not tested for, garanteed to kill at 50% though) does 22 dmg
When thrown it is significantly weaker
Blast Box 30 damage per explosion
Dragoon does 40 dmg
Warp star K.Os at 55% (mario grounded, direct hit)
23 dmg
Beam sword fsmash does 11 dmg does not K.O at >150%
Thrown K.Os at 130 does 14 dmg
Lip stick smash attack K.Os at 100% 17 dmg
Thrown does not K.O even at 300%
Hammer K.Os at 60% vertical 23 dmg
Golden hammer K.Os at 60% 30 dmg
Super scope thrown does not K.O at >150%
full charge shot K.Os at 75% does 28 dmg
full automatic does ~40 dmg
Ray gun shot does 4 dmg
when thrown K.Os at 153% 15 dmg
Fire flower ~7% dmg when thrown
Cracker launcher K.Os at 150~% when thrown + does 16 dmg
Single shot does not K.O at >150% does ? dmg
Pitfall - direct hit 16 dmg + meteor spike/bury
If planted into ground 10 dmg
Bumper - K.Os at >50 (O_o)
You may want to use these to supplement your arguments for/against x item.
Ray gun
ray gun lock
http://www.youtube.com/watch?v=dVMDotHmIvU
1:26 - end
^Is is possible for ganon to escape?
http://www.youtube.com/watch?v=pw5PcSYza0U
1:05 - marth death
^Not as good of an example as above though
Cracker launcher
http://www.youtube.com/watch?v=9RKvlCh36bA&feature=related
^Shows priority or something similar
Smart bombs for counterpick:
Yes they add more luck in that they can spawn into attacks, but they can be DIed out fairly easily. Aside from bumper, they might be the best anti-plank weapon in the game. Planking seems to be a problem in brawl. The range is so huge, detonate it as planker is grabbing the edge and they won't have enough invincibility frames to avoid all the damage. You said it K.O's at 140 which is quiet high. Not much risk but decent reward.
Pitfall for counterpick:
If hammer is counterpick, pitfall should be as well. Low risk, big reward. A fully charged smash attack from a lot/most/all of the cast can probably rival the hammer in power. The pitfall never goes squeaky either.
Big read huh? Took 3 hours to write all of this (so... please read...)
On a side note, why doesn't smash wiki list item damage output?
Copy and paste anything I posted here, wherever...