Microsoft already has three big blockbuster franchises. Halo, Gears of War and now Minecraft. However, I don't think this will be enough for Microsoft to be first place. What franchise could achieve this? I think overall, only COD will be able to do this. Maybe GTA, but that isn't a yearly title.

Cod is on a slow decline, although this years sales is on par with Ghosts, but I would still choose COD or Mario Kart (which is very unrealistic and will never happen)

Well, imo, I think GTA is more of a system seller than cod is... Just look at GTA V's sales! Sure, it doesn't get releases yearly but imo, it doesn't need to! The brand of GTA is way stronger than cod is so if MS buys GTA and makes it exclusive, a shit ton of fans will have a melt down and it will sell a shit ton of systems! (Unless they port it to the PC that is cause then the impact will be less but fanboys will cry none the less)

But at the sametime... Its not just about owning the IP... They also have to make sure they develop it correctly or else it wont really do anything

Nothing. Period.

One game does not make a console #1

Halo says hi...

However I think it's going to a number of games. COD would have a massive impact, along with games like GTA or straight just buying out EA.

Says hi to 24 million sales vs the PS2's 160 million lol!!!  Learn to read I said #1.  

There is no one single franchise that will bring about first place. They need a variety of them, which they have been doing pretty good at the past few months.

What about Halo? Has it given them first place in the console war...ever? Don't think so.

With out Halo, there would be no xbox at all, so essentially that one game saved a whole system.

LOL yes a console must have 1 game to sell at all.  What a brilliant (And off topic) point you just made.