by taking it as a joke
starting with "since the dawn/beginning of man/time/history..." is an infamous (supposed) sign of bad writing

: The fact remains that the Chief got from point A to point B, and there was an
: army of Covenant and Prometheans in the way. At some point in time, the
: Didact has to change up his tactics.

I guess so

: I really wouldn't be that surprised if the guys at 343i were that
: unimaginative, really.

really really?

: OK, you want the Didact to destroy and really present an obstacle? Have
: Cortana shout out a warning. Have the player run for the safety of a
: waypoint she lays out. Render the area impassable, and have Cortana think
: of a new way to get to their destination.

and that would be fine, except removing a few sections of floor isn't the same as that... until I hear differently, the most likely thing to me is that it's for gameplay reasons
they could have had him do something else that's more of a plot matter though, e.g. now you have to go disable this and push this button and destroy that before you can approach him, but then entire sections of the game were basically that already...