Posted this in another thread. If someone else has already mentioned this then great minds think alike.
IMO they should have a story mode. One with ALL the main quest (abridged in some ways) and a mission in between each quest (intro to each mission type) to teach you the mechanics. This story mode can take you to specific nodes with weaker enemies so that early game players can feel the power of the frames. Have loaner frames that disappear at the end of missions that the player can farm later if they want to. Heck, have Teshin show up early game to teach you stuff about how to play, how to mod, damage types etc. That way when things happen with Teshin later in the game/quest you'll feel it MORE. In other words, you don't have to play from mission to mission to catch up. Give rewards of essential mods as the rewards for the quest. Then boom open it up for the player to finish the starchart or chase specific frames or faff around in their orbiter after they finish the "Story". Then print money