Druid's aren't just nature priests; their is a fundamental theological difference between the Druid and the Cleric. The Cleric is a Priest who serves his god by spreading the word and bestowing the gods blessing on the faithful and virtuous in the form of healing (assuming a good-aligned cleric). The Druid however, has an affinity with the natural world that requires a certain ambivilance to suffering and death; those are necessary aspects of the wild and natural world. As such, I'm not sure it is appropriate that Druids be able to spontaneosly cast healing spells, as it somewhat goes against what a Druid is supposed to represent. The same is true to a lesser extent for the Ranger.
Well, these sorts of things are generally specific to how a DM and a campaign interpret the druid, but I certainly wouldn't say that yours is less valid than any other. My interpretation is that Life is a central part of a druid's theology, and, ultimately, things like suffering and death are manifestations of the struggle among living individuals. Hence, though they may be ambivalent, they have healing, but not inflicting, spells, because they are more interested in promoting life than in dealing death. Furthermore, IMC druids represent the "old religion", basically animism, calling on the spirit of Nature itself, whereas clerics depend on the intercession of an interested deity.
But my reasons for changing the druid are more about character balance and making them less of secondary characters. My analytical perspective is not so far off of what you described. Here is my general thinking:
1) First, my goal isn't necessarily to simply balance power; it's more to ensure that each character class is not "obsolete" but is attractive enough to be considered for play for more than RP reasons, and preferably as more than an "add-on" to a core class party. As you note, this isn't about some measure of total power so much as the roles that certain classes play.
2) The core classes are really the standards for the necessary roles in a party, and they are better at fulfilling those roles than any other class, as was intended. But these four classes are also the most flexible and have the best opportunities for fulfilling every facet of their roles. For example, a fighter can concentrate on melee, missile, or defense, but, over a long career with many feats, a high level fighter will excel at all of these things. A rogue has enough skill points to cover all of the most important roles, e.g., scouting, stealth, traps, etc. Clerics currently have the best healing, the best turning, extra spells per day, extra powers, and a powerful spell list, as well as decent weapons and the best armor. Wizards have a great spell list, an additional slot through specalization, and extra feats that allow them to be the best at magic item creation.
3) The secondary classes generally lose the flexibility of the core classes (fewer feats and skills, less powerful spell lists, no spontaneous casting) and replace it with a fixed set of powers of varying utility. In addition, many of their unique powers have limitations that cannot be easily overcome. A druid's animal companion and wild shape ability are severely limited by the nature of animals, particularly their low AC. There are no "animal enhancements" on their spell list to improve these powers, which should be the most attractive thing about them to a player. Thus, while a fighter has a myriad of feats with which to shape his combat role, and a cleric has the greatest flexibility possible in healing, the druid is only faced with a set progression and limitations regarding his primary powers. In some cases, this trade-off is not so unbalanced; paladins are still good frontline fighters despite not having lots of feats, and they have some very good powers in their place. But a druid, compared to a cleric, is giving up armor and weapons, a lot of general utility spells, spontaneous casting, domain spells and powers, and turning for a better Fort save, two more skill points per level, animal companions, wild shape, and several minor powers. Simply added together, these may seem balanced, but the druid is losing the most flexible things for fairly restricted powers like Nature Sense and Resist Nature's Lure.
4) What are the specific roles that the core classes play so well? Obviously combat for the fighter, but that includes melee, missile, and defense. Other classes can fulfill some of these roles, but not all, just as well. Even clerics can equal fighters in terms of defense. Barbarian rage can exceed the damage dealing melee potential of a core fighter. So, why should healing be solely the domain of the cleric, especially when that is not the only role at which they excel? Healing is one of the most important functions in a party. If you don't have a cleric in your party, then just about every other member must have some means of healing, even if it just means buying lots of potions. What party would rather have a druid than a cleric? Hence, druids are typically add-ons to a party with a cleric.
5) Will my changes make the cleric obsolete? Not at all. They are still great healers, and one with the healing domain is the best of all. Furthermore, their spell list includes restoration and resurrection, healing-type spells not found on the druid list, as well as many useful spells like magic weapon, greater magic weapon, bull's strength, endurance, bless, prayer, and sanctuary. Yes, druids have good spells, too, but many are restricted to outdoor use. On top of that, clerics are the best at turning undead. Even a party with a druid and a paladin will be missing something that a cleric could provide, such as a spell, a better turning attempt, or an extra well-armored body. And that doesn't even include the domain spells and powers.
The purpose of these changes is to break the absolute need for a cleric in a party and to allow for the possibility of a party without a cleric to still have healing. (It's bad enough that a cleric with the animal and plant domains can usurp much of a druid's power.) Theological explanations aside, the differences that existed between clerics and druids really came from two sources: 1) the perceived need to define clerics as the ultimate healers, and 2) the need to give the perception that clerics are more than healers. Thus clerics had the best healing spell list (a holdover from 1e), the most flexible access to healing spells (spontaneous casting), and some added non-healer features (domain spells and granted powers). Hence, the many "clerics are too powerful" threads. Yes, I am pumping up the druid towards the clerics lofty position, but none of these changes makes obsolete the roles played by other classes.
--Axe
