I am playing a druid, the RAW interpretation is a bit boring and relegates wildshape to a secondary ability (in my opinion) when it should be front and center.

I have changed the mechanic to be more similar to sorcery points or ki points.

You get 4 WS points per druid level (+8 points if mood druid)
Transformation is the CR x 4; min 1 point
Time in the form is 15min per point.

So for a mood druid transforming into a dire wolf (CR1), it would be 4 points to transform, and 1 point for the first 15 minutes. Spending a minimum of 5 points; out of your initial 16 point pool at level 2.

Non-moon druid transforms into a cat (CR 1/8), would cost the minimum 1 point to transform and 1 point for the first 15 minutes. Spending a minimum of 2 points; out of the 8 point pool at level 2.

The points still reset on a short rest.

At level 4 when non-moon druids get CR 1/2; the non-moon druid has 16 points; the moon druid has 24. At level 6 when a moon druid gets CR2 transformation they have 32 points. A CR2 transformation costs a minimum of 9 points for the first 15 minutes.

I like this because it means that wild shape becomes a resource to be used and managed like spell slots/ki points/sorcery points etc.....it also seems more progressive, as you become more experienced as a druid you can do more with the wild shape.

It also avoids the "wasted" wild shape feeling, so instead of thinking is it worth transforming into a rat to follow this target through a sewer, when I could become a crocodile later to mess up what they are heading toward....I think, rat for the next 30 / 45 minutes is only 4 points total, leaving me with 12 points in my pool because I was a horse an hour ago.