More than one catapult variant possible in the future?

[Lusitanio]

I think the AI would just shoot as before but instead of making two or three breaches on the wall it would probably just have enough ammo to do one and damage the towers. Still, for me it is already good as it is...

[QuintusSertorius]

Siege towers were not rare in our period. The Antigonids made use of them (especially Demetrios Poliorketes) before the game-start in several famous sieges (Rhodes, Athens).

[Lusitanio]

Siege towers were not rare in our period. The Antigonids made use of them (especially Demetrios Poliorketes) before the game-start in several famous sieges (Rhodes, Athens).

The Carthaginians also used them a lot during the Sicilian wars with the Greeks and the Romans may also have used them at that time, especially in the Lilybaeum siege. At least a bit later we know for sure they used it.

[James the Red]

Or we could increase the strenght of the walls so that artillery would do less damage overall and could eventualy destroy a part of the wall but at least not decimate it entirelly.

This sounds logical to me. Let the towers actually be a factor in sieges. Perhaps they should be, for balance and game-play reasons, fire projectiles that damage siege equipment a lot but otherwise don't fire fast enough to be much of a factor against units. Because the rams always get the gates. Destroy the rams and force the AI to fight for the walls.

Some further thoughts:
The problem is: we'd limit the only way to break the walls. The other two ways: sapping and ramming (non-wooden walls) are not possible. Nor you can build ramps. On the other hand, the siege towers were probably very rare in the ancient times (and used rather for bowmen and slingers to pelt the enemy, less to make a landing on the walls - this was for the ladders).

Is it possible to create an archer/slinger tower unit? Basically a slow chariot type thing with a lot of archers on top or something?

[Slaytaninc]

Since you can't sap, I think the artillery as it is is a useful if unfortunately inaccurate alternative. The factions that get these units are surely the only ones who were advanced enough to sap effectively anyway.