More to the point, the Soviets didn't really have an effective Strategic bomber force, but they were still fully capable of leveling Dresden. The He-111 may not have been a big bomber, but it's payload could be significant enough to do considerable damage if enough were deployed to an area that needed to be 'softened up'. The Lancasters and B-17 were only marginally better suited to the role of wide spread destruction, not because they carried that much bigger of a payload than the 111, but because they could travel much, much further into industrialized areas, that the German Bombers, quite frankly, couldn't get to.