The buffed the range and AoE because back when it was 40 and did almost no damage on the edges it was shit and nobody wanted to use it. It's an expensive investment and you can't get more than 1. The Sturmtiger is in a pretty much perfect place right now.
No one wanted to use it cuz you had to expose it and it was very fragile and ez to flank. Now that it can shoot thru buildings I thing its range could use a Slight adjustment as well as a Slight AOE change