[hoplitis]

Excuse me, are you comparing IEDs effectiveness with a """typical""" arty fire mission? Isn't it like comparing the effectiveness of antipersonel mines vs grenades or something similar? In any case IEDs or mines detonate on or in the immediate vincinity of a single target. The classical arty fire mission, in comparison to IEDs, is something like an "area" thing. Accurate targeting is possible with a high technology delivery platform, high tech projectile, high tech target observation system. You have those in the game (tactical air support with PGMs). But your enemy infanty woulde still qualify for a "I'll-pound-you-for-the-next-5-turns-with-all-my-arty" target.
In 10 years time... who knows?