Making things more open is kind of like an "Everybody wins" situation. I'm not seeing what they would lose by doing it.

I don't know the technical requirements for doing that so I'm not going to get into that.

Allowing Nintendo to do that will eliminate the issue of weak online community on the Wii U compared to PS360. So Nintendo has lots to gain while MS and Sony have almost none. That's from a business stand point. From a consumer stand point yeah if Nintendo does that everybody wins.

Not really.  Think of it this way.  With Black Ops 2 there's a whole seven people who play on the Wii U.  Yes, PS3 owners would be able to play with those same people, but they're gaining seven people.  Nintendo is gaining 100k to a million players.  Now for the gamer, yes, everyone wins.  But for console competition, this is a big win for Nintendo.

It's not hard to see why it's a big win for Nintendo only and may hurt another console competitor.  That's because if Nintendo markets the game as being able to play with all people from another platform, then it might have people who would normally get the PS3 version to get the Wii U version instead since they know that they'll still be able to play with their friends who are getting the PS3 version.

If it's a small game that sells few copies on both consoles or when the Wii U versions of games start selling as much as the PS3 versions, then there wouldn't be a reason not to as it won't hurt either company much but would be good for fans of the consoles. 

That's a fair point, which assumes that the PS3 has something to fear in the U, which I think is unreasonable in the COD market. Also, you're losing sight of the fact that the PS3 would gain 100k to a million players on xboxlive, so it's win-win for them there.

"Need" and "should" are not quiet the same. Pretty much the same difference as "assholes" and "maybe somewhat nice."

Criterion wanted cross platform play for Burnout Paradise but Microsoft has already made a statement that they wouldn't allow this.  In their words they'd have to give part of Xbox Live code which would damage the infrastructure.  In an interview, Criterion said Sony would be fine with it but it was Microsoft that wouldn't allow it. 

I tried Googling an article to link a source but I can't find it.  I did find a GAF thread that does mention Criterion and how they said they added a line of code so that they could still have cross platform leaderboards but PS3 and 360 owners won't get matched against each other.  The common response that there is no fee on the PS3 and people being able to play against each other this would hurt Xbox Live's image which is why Microsoft didn't want to include it. 

http://www.neogaf.com/forum/showthread.php?t=352196

With PS+ becomming mandatory for online play (I believe), is that still valid?

If Microsoft's quote about giving out some of the code for Xbox Live would damage the infrastructure and allow it to be hacked, then yeah.

Besides, PS+ is only becoming mandatory for the PS4.  I don't really think there are going to be many games that are going to be cross platform between PS4, Xbox One, and Wii U that also have online.

If they did, it might take a bit more effort making a game that's cross gen run multiplayer.  Devs probably wouldn't want to take the effort and money to do this.  Then it goes back to if the PS4 sells more than the Wii U and games aren't even close to the same install base.  Nintendo might nothing to lose and everything to gain.

@underlined. Yeah, I think MS is a bit proprietary like that. I'll hold to the idea that it's win-win but MS is opting against it.

@dev time. I never played blizzard games on mac, but I'd be curious as to how the server responded to requests from PC and mac gamers. Since the servers are receiving non PS or XB-specific code (it could be a common soap interface for all we know), then I don't see exactly how hard it would be to make it cross-platform compatible, imho.

Edit: Oh, wait. For xbox they are required to use the live servers and the xbox api aren't they?

Yeah they're forced to use Xbox Live servers, but when most of the games aren't dedicated servers and the servers only run matchmaking, I don't think it'd be impossible for them to atleast make matchmaking against other people in a different matchmaking server, especially when the leaderboards on the game were cross platform.  Then again I know zero about programming and only making my opinion based on what has been done.