Not exactly, 23 and 27 (Ford Field and Georgia Dome respectively) were not outdoors, they were in domed stadiums. Also, 19 and 26 were in retractable roof stadiums along with 25.
It will be in Dallas eventually(not 30), but trust me when I say they're not going to come within 25,000 of breaking the record. They want to I'm sure, and they'll try, but there's no way in hell they're going to sell 109,000 tickets. When they put WrestleMania XXV in Houston they wanted to break the record and ended up 20,000 short. Now the record is 18,000 higher than it was then.
Slight correction: Vince has stated ZERO times he prefers Mania to be in stadiums. The internet continually states it. I'm sure Vince agrees with it, but those words have never come out of his mouth, or the WWE's mouth in any official capacity.
That last statement is 100% contary to reality. There is absolutely nothing to suggest it's a done deal, or even that it's been discussed. In fact, there are two huge reasons to believe the rumor wouldn't be true - one, look at the OP. According to their sources, WWE hasn't even started talking about where WrestleMania 30 will be held. And second, a little thing called the Final Four.
Cowboys Stadium will host the Final Four on April 5 and 7, 2014. Given the time it takes to assemble and disassemble both the Final Four set and the WrestleMania set, that means Cowboys Stadium will be unavailable to host WrestleMania between March 16 and April 27, 2014.
I suppose it's possible they move WrestleMania forward or back that much, but it seems highly unlikely. Remember, holding WrestleMania the last week of March or the first week of April isn't just a tradition. They've built an entire yearly PPV schedule on it. If you have it on March 16, you have to push Elimination Chamber forward 2 or 3 weeks too. And if you do that, you have to push Royal Rumble forward 2 or 3 weeks too. And that would leave you with a lot less time than you're used to to build towards it. This is possible, since they used to have New Year's Revolution only a few weeks before Royal Rumble...but I'd think they made the change for a reason. Plus, what do you do with the schedule after WrestleMania? You don't need 6 weeks to build to Extreme Rules or whatever's after WrestleMania that year. That's enough time to put in an extra PPV between them, which I could see them doing.
If it's on April 27, you'd have to cancel the next PPV after WrestleMania. Plus you're talking about more than 2 full months between Elimination Chamber and WrestleMania. Do you move Elimination Chamber and Royal Rumble back a month, and put another PPV in January? That's what they'd have to do.
It's not worth the trouble. Especially when you can just wait until WrestleMania 31 to go to Cowboys Stadium.
Will WrestleMania XXX be at MSG? Probably, yeah. I mean, they treat house shows at MSG like they're TV shows, they treat TV shows at MSG like they're PPVs, they treat ordinary PPVs at MSG like they're huge PPVs. Being at MSG makes it one step bigger for WWE. They treat it like a huge stadium, despite the lower attendance. I see no reason to think they won't go back there for WrestleMania XXX. I wouldn't put much into it being in a close location two years in a row. Like others have said, IV and V were both in the same arena. Plus X and XI were very close to each other, New York and Connecticut. And others have been reasonably close - XIV and XV were in Boston and Philadelphia, 22 and 23 were in Chicago and Detroit, and XXVII and XXVIII were in Atlanta and Miami.
