Classic rant, Newman. You're in fine form. I hope it's not just the powerful painkillers.
Helton is still very productive, but Roxpert and SG have hit on the very disturbing trend. He's got those Bill James "Old Player Skills" to the max (the only thing that separates him from the classic formula is he's still good defensively). He's living off reputation and the ability to fight off/foul off good pitches. He rarely drives the ball anymore.
He is Mark Grace. Not the Mark Grace of his Cubbies prime; the Mark Grace of his Diamondbacks swan song. He is still helping this club win, but you've got to be scared. He's signed through 2011. At this rate of decline, there's no way he'll be a full-time player the last couple years of his contract. A Mark Sweeney at 20 million bucks? I think that's likely.
EDIT: Check this out. It is the precipitous decline of Todd's Isolated Power:
Todd Helton Stats and Graphs - Colorado Rockies | FanGraphs
EDIT 2: And this one. ISO splits. Note the sub-.100 ISO vs. LHP:
Todd Helton Stats and Graphs - Colorado Rockies | FanGraphs
So I'm starting to change my mind on Helton. It's too late to trade him. I think he can gradually morph into a part-time player. Good defense at 1B, still very effective (for now) against RHP, gradually becoming a platoon-type player, ultimately a 250 AB role player by his age 36 or so season. So maybe guys like Koshansky aren't really "blocked" at all. Maybe we need to keep him, and let Helton become a much more effective John Mabry type.