Self serving suggestion but It would be cool if clerics got something like this too (Although I appreciate clerics get domains which to some effect aid in this), whereby a druid can select a theme/background that would open up a selection of arcane spells otherwise not accessible to them:
Easiest Example would be my self serving example of "Ooze":
Open up Acid Splash, Melf's Acid Arrow, Mestil's Acid Breath, Acid Orb, Mestil's Acid Sheath, Acid Fog
Another example would be elemental druid:
Fire: Burning Bolt, Burning Hands, Combust, Fireball, Elemental Shield, Firebrand, Delayed Blast Fireball.
At the moment druids really just seem like they always prepare the same spells with little variety.
Not really possible without adding a lot of restrictions via scripts to handle each "theme".
Even if was easy to implement, I think Ooze is already well represented already, and for "elemental druid" it's a sort of lazy implementation to just add elemental spells, instead of having something more special.
Of course suggestions for druid "kits" are always welcomed, but unless it's something that really changes the flow, the RP, or the way to play a Druid, it probably won't happen. Adding a bunch of spells, or increasing by 2 a Skill or two, is just some minor bonus that won't really change anything for Druids (and that the Druid class doesn't really need).