Seath
Bed of Chaos
Artorias
Ornstein and Smough
Taurus Demon
Personal Top5. Such BS. Long way from bonfire. Strong enemies in the way. Dark Souls 3 feels like a light breeze compared to that.
You are right - DS3 is very generous with boss shortcuts. Surprisingly enough, I'd say Taurus Demon was probably the hardest route for players trying to get their bearings.