Zurai
First Post
The Cleric and Druid spell lists are, IMO, roughly equal. Clerics get earlier and better heals and better self-buffs; druids get earlier and better nukes and better party-buffs. Basically, again IMO, clerics are more defensively focused, while druids are more offensively focused, with regards to their spell lists only.
That being given, I'd say there's no reason to disallow swapping a cleric's list for a druid's list in their entirety. There are reasons to disallow cherry picking (PHB example: clerics get heal at level 5 vs 6 for druids, while druids get flame strike at level 4 vs 5 for clerics. If you allowed cherry-picking, you could have the same character with level 4 flame strike and level 5 heal. Of course, then there's Archivists... but they have a worse HD than either class and worse physical combat abilities).
That being given, I'd say there's no reason to disallow swapping a cleric's list for a druid's list in their entirety. There are reasons to disallow cherry picking (PHB example: clerics get heal at level 5 vs 6 for druids, while druids get flame strike at level 4 vs 5 for clerics. If you allowed cherry-picking, you could have the same character with level 4 flame strike and level 5 heal. Of course, then there's Archivists... but they have a worse HD than either class and worse physical combat abilities).