Exiling is the only way to deal with Blightsteel Colossus permanently
They don't copy whether that creature was tapped or untapped, whether it had any counters on it or Auras and Equipment attached to it, and so on
While Red doesnt have a ton of self mill going on, theres enough rummaging with Blood that I think getting this set up to give you that 3/2 in the mid-to-the late game isnt too crazy, though you probably shouldnt really expect to generate more than 2 or 3, even in ideal situations but 2 or 3 is plenty
They eat fewer creatures while blocking and often cant stop opposing three mana creatures
Since youre able to generate a massive amount of mana using Nykthos, Shrine to Nyx, you can destroy your opponents hand and life total as early as turn 4
If there's a cost associated with having a creature block the attacking creature, the defending player isn't forced to pay that cost, so it doesn't have to block in that case either