The regular Stug already counters light tanks. The Stug E not so much, but that's not what it's there for. I'm not really sure what to do with it if the regular stug were to get some better AI ability (again, via a shell swap like the M4, not by buffing the regular attack. I feel I should stress that highly)
i disagree, the regular stug is too slow to counter light tanks. You can skirt a aec around it to kill stug easily.
regular stug is only good to supplement against IS and Churchill tanks.