Yes, archers could be improved.
As an Xpyre said, the Tarth fraction should have a an archer oriented research and build strategy.
The AI needs better archer counter tactical strategies. For me its usually a choice of do I target enemy archers first with a ranged attack or cast Gust of Wind to protect my units. If the human player is using archers then counter with mounted units or ranged units. Just once, I wish that the AI would use a ranged based attack strategy against my Kingdom (i.e. archers + fire staffs + catapult + ranged attacks from champtions).
I would like to see a greater variety of bows - short bow with a limited range, long bow with a longer training time, compound bow and a variety of bow related traits (accuracy +10%, Rapid Fire +2 initiative), Crossbow with a longer reload time and a shorter training time.
Perhaps, a trait called: Arrow Shield, that gives units with shields the option to use a tactical strategy (like fortify) that provides a bonus to their ranged defense at the cost of losing a movement point (you move slower with a shield raised above your head).