An additional game mode where the waves are static / seeded such that each run you do has the same enemies at the same points (ideally with the same elite / champion status excepting mods that override this.) It could also include the order of modules and gears for an even more consistent experience.
This mode would allow for a more consistent gameplay experience useful for balance testing, practice, and targeted competition between friends.
Assuming that the Daily Challenge mode is going to be implemented in such a way that people have to deal with the same gameplay mutations, it stands to reason that there could be a similar mode where they have to deal with the same standard gameplay as well.
As one example of a game that does this relatively well, Bloons TD 5/6 has the same waves every game up to a certain point at which they become random. This could allow player knowledge to be more meaningful up to a point where reaction and build limits take over.