Titanfall 1 was multiplayer-only, so I don't think you're missing much by skipping the original. Though I haven't played Titanfall 2 yet, still waiting for that bargain bin price it will inevitably drop to (I know, I'm part of the problem as to why this game sold so poorly).
MGS5 is fantastic despite it being kind of an unfinished game. You don't really need to play MGS3 or 4 to understand the story. It's surprisingly easy to get into. Gameplay is the series' best, IMO.