This is my feeling too. I don't like the thought that I'm not getting the full experience of a game because I missed a pre-order bonus. I'm not big on t-shirts because they're usually only available in XL so I can't even wear it.
Agreed, but these days it seems more typical that the bonuses do affect gameplay. I'm seeing fewer t-shirt and poster bonuses. In Dead Rising 2, the ninja outfit makes a huge difference in the gameplay.