I wouldn't have to change my lenses that much. A f2.8 /f4 and even f5.6 would haven given me the DoF that i want. Now I often have to go with f2 or even f1.4 to get the same dramatic effect.
...But there's a BIG BONUS to having to shoot at f/1.4 or f/2.0, you get to shoot with MUCH lower ISO speeds.
For example shooting with natural light at f/2.0 with an AF-100 or GH-2 might require an 800 ISO rating, but shooting at f/4.0 with a Canon 5D MK2 would REQUIRE an ISO rating of 3200 for the SAME DOF and SAME exposure.
This changes things in a BIG WAY, especially with Voightlander now making a 17.5mm f/0.95 M4/3 wide angle prime lens and a 25mm f/0.95 M4/3 standard prime lens. Hopefully there will be more super speed Voightlander lenses in the future. Imagine a 12mm f/0.95 prime lens!