Slitherine

I found my new favorite unit to storm cities:

The armenian catapract
It has attack 6 - a lot of hitpoints, very high defense vs ranged and no clumsy stat. Thus it obliterates even greek medium infantry with good archers defending.

Not good for the game though.
But they have some kind of wings to fly over the walls.

You should try the Sarmatian cataphracts, then! Armenian ones are incredible for countering mountain/alpine penalties through their mountainmen perk and are nearly undefeatable in hills, but Sarmatian ones (available only through Sarmatia meridionalis AFAIK, north of the Chersonesus province/modern Crymea) rule the field unopposed on plains & steppes. The real downside being the frontage of such terrain - if you want a powerful front line, their recruitment cost & upkeep is unsurprisingly costly!

Armenia is a great nation to play. They have a lot of high quality units and you can recreate the Armenian Empire pretty easily.

Armenia is a very interesting faction to play. There are only a few nation people have to pay extra attention to region type malus and rivers, Armenia one of them.

In order to fully use the strength of cataphracts, there shouldn't be any infantries mixed in the troops. For Armenians heavy infantries only have defensive use.