Agree with the conclusion that order is simply better than autocracy for domination games. Aside from the policies being better, order enables faith-purchasing GE's, which are ALWAYS extremely beneficial, whereas autocracy enables GG's and GAd's, both of which you'll end up with more than you could possibly know what to do with anyway during a dom game (save possibly Sweden).
Just to play devil's advocate though, autocracy can be fun for a few reasons:
1.)autocracy mixed with economics (another good dom choice) provides 2 cumulative policies which reduce the gold-purchase price of units. Both of these plus Big Ben enables purchasing tons of units every turn (and the maintenance is manageable due to the opener)
2.) the happiness bonus of order is a flat 1/city. If you set up your dominating empire as a tall/narrow empire (perhaps with a tradition 4-city opener) and later expand exclusively through conquest, the vast majority of your cities will be annexed spoils of war (if you're a control-freak like me, otherwise just leave 'em puppets). If this is your choice, you'll end up with more happiness than order as each annex will provide 3 extra happiness with a courthouse.
3.)The finisher does help substantially in wrapping things up.
4.)Just to do something different; seriously, other than deity games (and culture games), picking between the 3 industrial-era-unlocked SP trees tends to be more "icing on the cake" than really decisive measures, such as picking between tradition or liberty.