Totally agree. The gene splice that keeps devolve costs from increasing is basically an automatic win on most modes, as long as you have patience. As soon as you mutate a symptom, immediately devolve it, and nobody will notice you until you reach 100% infection. At that point, as long as you have saved up enough DNA points to go super-lethal all at once, you win.
That’s why Bioweapon is so hard for me–because I haven’t yet figured out how to stay under the radar long enough to have finished infecting people.