It's wonderful to see a lot of FanPost Friday responses this week. I'll try to be brief with mine.
My answer will be boring compared to some of the others here. But hey, I like things the way I like them.
I'm not in this one for pace-of-play changes. I'm not a big fan of crazy rules designed to force the game to go faster. Part of the appeal of baseball is its slow pace. We get to slow life down when we watch or listen to baseball. The Baseball Gods tried to tell us this by making Trevor Story such a ... well, story at the start of 2016. "Hey, fans, baseball is a Story, not an action flick!". That's what they were telling us. What, you didn't pick up on that? Oh well. Sigh.
But this modern world doesn't often give us 3 or 4 hours of free time to take in a game. So six hours for a 19 inning game? Hardly. Few of us can afford that much free time. So I guess cutting extra innings shorter makes some sense.
I'm not fond of crazy ideas that would change the structure of the game, either. Starting innings with runners on base? Really? Like yuj said, we'd have to keep a completely different set of stats for that. I don't want to see that either.
I prefer a minimalist approach ... allow ties in regular season games. But don't declare a tie until after 12 innings.
Why not declare a tie after 9 innings? Two reasons.
First, I wouldn't want to deny OOLF his free baseball.
Second, a lot of us won't like the idea of ties, so we want to minimize these. Currently, a little over 80% of all extra inning games end by the end of 12 innings. This number could change a bit if we allow ties due to changes in strategy (your closer coming in for the 12 would pretty much be automatic), but still we'd expect something close to 80% of extra inning games being resolved without a tie.
Why 12 innings instead of 11 or 13? A few reasons.
11 innings wouldn't eliminate enough ties - the percentage of extra inning games ending without a tie would be somewhere in the 60's.
13 innings would mean 88% to 94% of extra inning games wouldn't end in a tie, but baseball fans are superstitious folks, so 13 just won't do.
Plus, it means 3 extra innings, and as I've pointed out before, the Baseball Gods love the number 3.
Also, I don't think OOLF would be satisfied with just 2 extra innings.
12 seems right. It's about what I think when I see a game going into extra innings ... "Well, I'll watch a few extra innings, but I don't want to go beyond 11 or 12". And then you have to worry that if you do watch through the 12th, and it's not over and you leave or shut it off, that the extra time you put in didn't reward you with seeing the conclusion of the game. So maybe you shouldn't even watch that much. Well maybe just a little. Wait, what if it suddenly ends next inning with a dramatic walk-off? That would suck that I turned it off just before that ...
All of that is fixed if we cap it at 12. You don't have to wonder if you'll miss anything or not ... you can keep watching, get your three free innings, see the game end, and still maybe get to bed on time.