Maybe the Ori care about the universe and don't want to waste more energy than necessary

This way they fired at low level settings and estimated how much energy they'd have to waste destroying our puny vessels.
Both the Ha'tak vessels and Asgard vessel used evasive measures, from which we can deduct Earth really isn't that smart and don't have the ability to learn from other races.
What I found most sad was that the Tau'ri took control over the whole MW-fleet when they arrived. Shouldn't the Asgard with the most powerful ship in our fleet, and with the most technological knowledge and the best standard military ship-ship engagement tactics take command?
Also, why didn't the Ha'tak use remote controlled Death Gliders at high PSL to do suicide runs, they would do several magnitues more damage than the Ha'tak bolts. Why didn't they prepare high PSL rock throwing like the Wraith did in The Siege?
The Ori Toilets had very unarmored sublight engines, so if they broke through the shields that is what I'd like to hit. Either that or the main weapon emitter.