What I always loved about BL2 was the fact you could pretty much climb anywhere inside (And outside) the map. Your only limit was the amount of your grenades and small amount of invisible walls.
In BL3, you cant really climb anywhere where you arent supposed to. Do you want to climb up somewhere where you arent supposed to be? There wont be a prompt to climb up. Thats it, You are done there. And even if you managed to climb up somewhere, You wont be able to get anywhere because everything is solid or you will just hit a invisible wall (Which are pretty much everywhere).
Even though this is a quite niche activity, The fact that its not possible in BL3 has made me enjoy it less.