SenjutsuSage
Banned
Which is why I'm making sure to do all side activities before progressing each story mission.
I briefly stepped away from doing this to dig into main story, but thankfully I was given a second chance before pushing forward more in story. I will not make that mistake again. I will complete all side objectives before pushing forward with anymore story from here on out.
I see the way 343 handled this initial scare of not having access to the open world to complete side objectives as a very good way to signal to the player "hey, we're going to get into some story moments that will occupy you in specific places, so you might want to do all those activities in the open world if you want any chance of doing them again before endgame."