I'm in the camp of those who are opposed to civ3 style ranged bombardment for artillery type units.
The reason is gameplay related and has to do with the turnbased nature of the game. Every unit in the game can die when it attacks and with good reason. If you have units that can damage the opponent without any risk, then you will create as many of those as possible and hide them underneath other units that can protect them. Any unit or stack of units that you encounter will be weakened as much as possible by these units that can attack without risk of being damaged and then the pitiful remainder of the enemy stack will be destroyed by normal units that can die when they attack. However, they won't die as the enemy units are weakened to the extent that their chance of defending themselves successfully is close to 0%.
The problem with this model of war is that the turnbased nature of the game will result in no form of protection against these bombarding units. In a real time game, you can try to move around or over the protecting units and hit the bombarding units, but in a turn based game you will have to wait until it is your turn. You will have to sit and endure the bombardment while your units cannot counterattack. So typically, victory in combat will go to the side who's turn it is and can use the bombarding units to obliterate the defending armies. It's hugely unrealistic that armies would sit there and endure the bombardment.
The reason why the bombard model for bombers works is because there is a unit that can counterattack them during the bombers turn, namely fighters and ground based anti-air units.
If you add a unit that can bombard without any form or possibility of counterattack during the bombarding units turn, then this unit will dominate the game. The attacker will have a huge advantage as the attacker can use the bombardment units to weaken the defender to the point that victory is ensured.