Agreed, tho I'm not sure how to implement this without breaking the game lol
The missions rarely lock you in a path though. And I also always give players the chance to safely do whatever they want (like pick side quests, sell items etc) at the end of every chapter, before handing the money. I call it a limbo between chapters xD
Also none of the side quests are missable now, so you can literally do them anytime you like as long as you have your whole party with you. So if you don't feel like doing any now, feel free to leave them for later. Just beware that giving the receptionist the money at the end of a main mission will dispatch your companions and start the next chapter! And if you you're in the middle of a quest but don't feel like doing it anymore, most times you can just leave the area and do something else instead.
I hope that helps!