Capn Bloggs:
Do the designers honestly believe that increasing the vis requirement to 1nm (less than the length of a runway) is going to enable a satisfactory visual terrain avoidance manoeuvre after takeoff? In less than 30 seconds, you have to visually identify the obstacle, work out whether or not you are going to hit it, and then manoeuvre laterally to avoid it, all with an engine out?
First and foremost: the designers are
not charged with designing a departure procedure to provide for an engine failure. That is solely the operator's responsibility.
Now, do designers provide a visibility requirement for close-in obstacles that they honest believe will aid in the avoidance of the obstacle? No, they are usually not pilots, and even the few that are have no heavy, or significant line experience. The flight inspection pilots are suppose to be the "check valve" but they are often checking off the numbers on a nice clear day.
Plus, takeoff minimums have a larger political component (and less science) than do landing minimums.