Preorders are vital for an publisher, because that means they sell an large amount new and not lose out on used titles. Now they are even more desperate for your pre order offering an wide range of DLC, limited editions etc. 

But none of the stuff they offer at stores like gamestop/eb/game etc are not that drawing for an gamer to pre order an game they know they could pick up on day one anyways unless its cod or gta. 

The only one who really got the pre ordering or Pre purchasing right has been Valve, offering far better goodies such as free games which are usally its precessor if its an sequal, an someone they offer the best pre order bonus of them all: 

A DISCOUNT!

Why oh why haven't every publisher and retailer dont do this at box stores amazes me. 1. for the publisher: it equals more new copy sales on day one, and reduces potiental use game buyers. An retailers like GameStop/Eb/game should do this to get more people to go there gaming stores rather bestbuy or target or an major supermarket. 

Now valve offer an 5-10% discount, they did it for Portal 2 and some Publishers do it because its DD, they make an killing of every sale. Maybe the Publishers dont want to reduce there day one sales because 10% off on possible 100s of thousands of units might not offset the loses instead of having none at all. But at first they will maybe make some less money, but if all the publishers do this on an regular basis, the numbers for preorders will most likely double or even triple in number and first week sales could all be pre ordered and result in increased revenue because more new units where sold. 

I think getting the game early is the best reward, which I get from GAME, but if you are looking for discounts then pepole will wait until after launch as that is when you are going to get it cheap

Amazon tends to have games around 10% off at some point before they are released.  Plus they often have $10-20 credits to go along with it.  For example I just got Portal 2 for around $55 and I received a $20 credit.

I don't really get your final point though.  I can't really see an individual game being better off when everyone is giving a preorder discount than if it was only that one game.  I just can't see millions of extra people preordering for $5-6 off.  Especially when they could probably wait a week and get a better deal than that.

millions is an bit over the top. But lets say  the typical release gets around 100k preorders and sell around 200k first week, having an neat discount could draw over that extra 100k of first week buyers if the publishers and retailers program into the consumer to pre order the game. Because those first week buyers, they know when the games coming out, and something may make them not pick it up first week, and when that happens then the publisher may lose out because that gamer may buy used. So having all those first week buyers who cant be bothered to pre order, pre order. Then that could be benfitial in the long run for publishers selling more new copies. 

I dunno man...I think the Gamestop preorder bonus for inFamous 2 are pretty badass

The best pre-order bonus is a confirmation from the developer that I am buying the complete game and not 90% of the game with a few mission/weapon/characters etc cut out that will become 'cool pre-order content'.

I would love behind the scenes stuff like in-game commentary

I would like my pre order to come with all this;

Well.. it would be nice..

I know right? that soccer ball does look great

dam! i would so go for those Socks, I wish they put them in fifa pre order. 

anyways i would love to be the coach of that team