In the case of Mass Effect 2 there was more exclusive preorder content, and retail exclusives then there was armor in the game.
Yeah, but the armor in the game was *useful* (modular, pick your bonuses, colorizable, etc), while the pre-order bonus armor (at least the one I got from Gamestop) was garbage. And ugly.
Preorder bonuses used to be physical items. Like the junk I got from various Squaresoft games in the PS2 era - zipper pulls (Parasite Eve 2), crappy plastic alarm clock (Chrono Cross), posters (Star Ocean 3), and soundtrack mini-CDs (Legend of Mana?). Nowadays, they've discovered that digital bonuses are both 1) cheaper, since there's no manufacturing cost and it's easier to send a store a stack of code cards; and 2) more attractive, since they're actually things that you can use in-game.
But it's still the same old "please pre-order, so we know how much to order!" combined with "buy it from us instead of them! Here's a bribe!"
/shrug
Edit:
If it's complete in time for launch, put it on the disc and quit being so greedy.
Huh. How is pre-order bonuses (i.e, no extra charge for them, just something extra - for free - for saying ahead of time that you'll buy the game) an issue of "greed"? If they were $5 DLC packs, you might have a case, but..... (and they certainly aren't expecting people to pre-order multiple copies from different stores to "catch 'em all". Crazy people may do that, but you don't design your market plans around them.)
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But, yeah.... the content hints (repair kits, poison, throwing weapons, binoculars, etc) are the best part.