[Graeme Dice]

They are also quite slow on expansion, rarely I managed to capture another province before turn 5.

What independent setting are you playing on? I rarely have to wait past turn two to take my first province as Mictlan, and that's playing at sloth 3 with a watchtower and a smoking mirror pretender with a large amount of magic. With 4 slaves out front to take the initial arrows of any archers, 6 jaguar warriors on the flanks, and the rest of the units attacking in the middle most light infantry and archer provinces can be captured with little difficulty.