D&D 5E Wildshape with Spell Slots

[TheHand]

So in an upcoming game, one of my players wants to play a Druid inspired by the movie (Honor Among Thieves). I remember seeing some discussion a month or two back where someone proposed using spell slots in place of a class resource in order to Wildshape, and that got me thinking. I think this theoretical druid used spell slots to also turn into more powerful forms, so for example a Level 1 Spell Slot might let you turn into a CR 1 creature, and a Level 3 Spell Slot might let you turn into a CR 3 form.

I'm willing to try to homebrew this as a druid subclass 'replacement' for Circle of the Moon, but before venturing into the unknown I thought I would see if anyone has already tried something like this, and if they had, what kind of experience they had with it. Any pitfalls, balance issues, suggestions?

 

[jgsugden]

I would not change anything except adding a Wildshape Spell (druid only) that allows a druid to Wildshape for 1 minute into forms as follows:

Spell Level 1: CR 1/8 or less (ignore burrow, climb, swim or fly speeds)
Spell Level 2: CR 1/4 or less (ignore burrow, swim or fly speeds)
Spell Level 3: CR 1/2 or less (ignore swim or fly speeds)
Spell Level 4: CR 1/2 or less (ignore fly speeds)
Spell Level 5: CR 1 or less (no movement restrictions) - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 6: CR 1 or less, duration 10 mins - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 7: CR 1 or less, duration 1 hour - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 8: CR 1 or less, duration 4 hours - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 9: CR 1 or less, duration 8 hours - Monstrosities allowed (ignore magical abilities - DM discretion).

... and a version for Moon Druids (only available to Moon Druids):

Spell Level 1: CR 1 or less (ignore burrow, climb, swim or fly speeds)
Spell Level 2: CR 1 or less (ignore burrow, swim or fly speeds)
Spell Level 3: CR 2 or less (ignore swim or fly speeds)
Spell Level 4: CR 2 or less (ignore fly speeds)
Spell Level 5: CR 3 or less (no movement restrictions) - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 6: CR 3 or less, duration 10 mins - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 7: CR 4 or less, duration 1 hour - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 8: CR 5 or less, duration 4 hours - Monstrosities allowed (ignore magical abilities - DM discretion)
Spell Level 9: CR 5 or less, duration 8 hours - Monstrosities allowed (ignore magical abilities - DM discretion).

In both cases, I'd have a caveat allowing you to upcast only if you have the requisite levels in Druid to have that level of spell spots. You can't take 2 levels of Moon Druid and then use a 7th level spell to get most of the benefits of being a Moon Druid.