My 2 cents...I don't believe a sub Vmc take off in a C340 is that dangerous...but requires a certain mindset. Luck favors the prepared.
Most of us(I think) started out in singles, and should have been springloaded for and engine out scenario for an off airport landing. Having been a flight instructor doing 20 engine outs a week...prepared me for a real 15 mile unintended glide..
Once I got into light twins, the mindset was to fly. Surprise, surprise light twins and many turboprops do about 300 FPM on one engine if the conditions are right, and the pilot knows what he's doing. So I had to keep in the back of my mind that I might still have to put the plane down somewhere after take off...enroute probably not.
Can't argue that planning VR after Vmc is prudent...but the ops might require short field, or soft field techniques...so the mindset is to understand that sub Vmc engine out, you pull the power back untill the roll tendency goes away, given the appropriate control surface deflections. The plane will probably not go up, but it might stay level or descend at a slower rate then a single..
I have felt under these scenarios..getting the plane off the ground, then accelerate past Vmc, in or near ground effect, talkes almost little time...and your there...
Taken that all the above doesnt work given the conditions your back to being like a single, a glider, looking for a place to land...thousands of pilots think like this every day...