For me, there's a simple solution. In a case like that, I pre-order the game anyway (just in case) and if I end up still not caring when the game is released, then I cancel my pre-order and put the money on something else. It appears that the map pack that comes with the pre-order is going to be released to the general public at one point as-is; it just might cost a few dollars.
And this is fine. And if the weapons would be also I would be (more) okay with it.
But right now I have no reason to buy it. I don't know anyone who's going to buy it and I don't have any reason to think I'll have someone to play with. After it launches I may find out that half my friends are all playing it and love it and want to join in. Annnd I have no way to get these items. So I should pre-order it on the chance that I might have some reason to play later? Fat chance.
Pre-orders serve two functions. First, they are a decent gauge of how interested the public is in the game. Second, they reward people who pick up the game at launch.
Pre-orders have been going on for YEARS. Pre-order bonuses, by definition, is usually stuff that you can only get by pre-ordering the game. Why did we chose Battlefield 3 as the "criminals" here when a excrementload of other games do the same thing? I didn't see ANYONE bitching about Dragon Age 2 pre-orders having $20 of bonus content and a free limited edition.
By your pricing I assume you could buy the stuff later. That's one reason I don't complain. Second it's single player, so I'm not actually hurt by your having it. I have -no- issue with DLC itself. I have no issue with packaging DLC with pre-orders as a incentive to pre-order. I have a problem with pre-orders getting things that are not available to non-pre-orders and affect gameplay. Reskin? whatever. Extra goodies in the box? Great. Early unlock of things you normally have to work for? Fine.
And I am complaining about the ME2 pre-order bonuses. I don't have DA2 or any plans to get it and it's launch is already past so it's not news for me to weigh in on.