Warframe's daily reward system was recently updated for the first time since its inception over 1000 days ago. It now scales in proportion to player rank, which in this game would translate to levels. piggybacking on Jabberwockie, I think this is indeed an important thing to consider. I am now getting 31 hour boosters or 6 rare materials instead of 3 hour booster or 1 material.
Give players a choice to pick gold, or xp boost, or faction points for any faction, on a daily basis, would definitely generate interest in consistent play. Scale it in proportion to level.
this sounds amazing and i know some games give you the login reward for just logging in, but i feel it be more natural to spacelords if it was like a "First of the day" kind of reward where you do a mission to get them