I haven't played version .01 since so long ago that I've forgotten that there is no martial law cap. Is this a dream?
Monarchy still works in .05 but only under certain circumstances. You can go for it early for growth and production, especially if you get some starting tech that leads to it (sometimes you get 4 techs and you can even start with it), but you have to have good tiles--game, fish, oil, river, etc. WLTK is definitely the way to go, but not necessarily in all cities, just the best trading ones. A big city with good trade routes and a marketplace and bank can keep its republican level trade output up at 20% luxuries. Bump up to 30-40 for one turn to get it to celebrate, then when it gets the bonus trade you can bring luxuries down a notch and the city will still be happy. With martial law and no unhappiness for roaming units, quelling riots and defending borders becomes very easy. The only problem is slow growth. The solution is to switch to republic during peacetime, bring in or disband units that are outside of your cities, grow, switch back to monarchy/communism when you max out. This is quite useful if the AI beats you to Bach's and Women's Suffrage and you're waging too many wars to deal with the unhappiness. The freedom of being able to break treaties at will and demand tribute is also a bonus. If you're strong, you can get a lot of cash this way.