User blog comment:Zephyrus11221/On the Topic of Seven Stars and Low Level Players: Why?/@comment-153.107.192.205-20151113014503/@comment-26336535-20151113022624

Exactly! 7* units aren't necessary for the dungeons players encounter at levels 40-70, yet I see people still trying to get 7* units. Just use the 6* units. If people before you could manage with 5* or 4* units in those dungeons, you should be able to as well.

As another note though, Miku is no longer available for new players, so it's kind of pointless mentioning her as an option for them. Of course, Mifune and Lario are amazing units (though they only fill one role), especially for 6*, 25 cost units.