1. I had the Sarmatians on 3 different occasions, each time they were nowhere near being worth thier cost in battle. I admit in 2 of the battles I mearly threw them at the enemy just to see what they could do.

2. I've had both of these problems aswell. Things like the archers being split and not firing is just one of many crazy bugs that happen in sieges with manned walls and lots of siege equipment.

As for the enemy freezing it happens to me quite often in seiges, most of the time it seems to happen becuase the AI doesent know how to proceed with it's attack. If you deny enough of it's tactical options it runs out of scripts or something. (speculation)

3. Yes, I took it for granted the first time I saw it but now that I think about it's cool they provided for this but then again if you couldent do it people would be complaining about it :)