"Active" is actually *trying* to find or perceive something. It's based on how well you put clues together and quickly make sound deductions.
Observe, even as you state it, is still pretty much "finding things, and putting 2 and 2 together", not "having a knowledge base on the value of items".
A country bumpkin might be able to make out the tripwire that is attached to the doorframe that will set off a trap... but not be able to tell the difference between pyrite and gold, or cubic zirconia and diamond. Or a gem and colored glass... or even cooking beans and a magical item that will lead to the realm of the giants in the sky.
As for the case of "Appraise is lame".. well, you could say that about a good number of skills. For a regular dungeon crawl, kill things and take their stuff, campaign you could honestly knock out Appraise, Craft, Diplomacy, Disguise, Forgery, Gather Information, Handle Animal, Heal, Knowledge, Perform, Profession, Ride, Sleight of Hand and Speak Language (hell, languages in general) and feel little to no effects.
Hell, if Bluff and Intimidate didn't have in-combat applications, they'd be on that list too.
So yeah... in a game where you never need to use most of those skills, you could just take them out or wrap them into something else and be done with it. Adventures have to go out of the way to find reason for putting these skills into a dungeon crawl.. so really, why have any of them, right?
Well, core rules aren't there so you can play only dungeon crawls... it's so other people can play any game style they want. Appraise isn't lame in a game that has a living economy, or is heavily based in a theme around valuable items (such as a Thief based campaign setting).
About the only thing you've convinced me is that you could roll the magic item identification into your Observe and write Appraise out of the game. Just like you can go the "Star Trek" route and write Languages out of the game and just tell the players they either understand what's being said by default, or they are speaking "in some foreign language" so you need to cast the right spell or just can't understand it, etc.
That's an awesome House Rule that would make standard dungeon crawl, high action gaming a little less messy. However, for a Core Rules book it would be neglecting a game style that was possible with the 3.5e rules.