I don't know what was the size of this siege of Alowca but from the name I am guessing it is on colonies which is too small of a sample size. Plus it is just a single siege with unknown number of different unit types. So you will need to give me more details for that one. Sounds like this Alowca was poorly prepared and got overwhelmed by gang up attacks from your story though.
The most effective siege tactic at the moment is to put your archers in skirmish and set them in the front with 1 infantry in each row with the rear having all other unit types except cavalry. Cavalry need to be set in the back to prevent them from charging into the walls.
Or if your archers outnumber enemy archers 2 to 1 and they only have a couple to few infantry units, you only send ranged units and set them in middle or back to take out infantry units.
As for out ranging your enemies that is not feasible in most cases. Almost no one runs pure R5 units and it is a dumb idea to only have an army full of SFs. Plus if your enemies have R5, it doesn't work. So give me an example of a siege that is more equal.
As for your suggestion regarding the new siege status, it looks like we just need some additional codes to the TO mechanic since TO already prevents some stuff.
