Mercule said:
Unfortunately, that's just not possible. It essentially turns one class into two, each of which has its own balance points.
Actually, I think it's infinitely possible (but that's the great thing about America; we're all free to disagree)! Here how I so it:
Rangers get X Y-level spell slots per day at level Z. I allow them to trade in a slot (which can normally be used to power any Y-level spell) for certain of the abilities normally granted by a spell, and allow it to be usable dependent upon power. Usually, this is limited to Divination and some protection spells (here's where the balance gets tricky).
For example, a fourth-level Ranger with 12+ Wisdom gets one bonus 1rst-level spell/day. He trades this in for
Speak with Animals, and now has a Spell-like ability, usable at will.
Yes, the SwA is now much more powerful, but the Ranger has traded in the use of any other spell in return for that option. Balanced (IMO).
At 7th level, he picks up another 1rst-level spell. He can trade that away for
Endure Elements: Cold, gaining five points of resistance to cold, but never allowing him to use other spells. Once again, he has traded in versatility for constant use (and gained nothing, in this case, since the spell ordinarily lasts 24 hours). (Yes, I know 3e Rangers can't cast
Endure Elements - I gave it to them, in my version, as well as Orisons and other spells).
Now some spell-like effects (
Cure Light Wounds and other healing spells,
Protection from Elements, etc.), have to be limited to once per day use (making it a bit odd to remove them as spells in the first place), but with some balancing on how often spells are usable, it can (and does!) work.
But that's not the only way! There's also another method that also works!
The other method is to allow Rangers Bonus Feats, and have one or more of those grant spell use! Those who think Rangers shouldn't cast can take other forms of abilities which are mundane.
Either of these two methods should work. In my version, I put the two together, granting spell use automatically, but granting individual Ranger-Only Feats which traded a spell slot for a supernatural ability (thus requiring a loss of flexibility & utility, as well as "burning" a Ranger-Only Feat).
Ymmv. It works for me. Don't want a Ranger who tosses spells? Try one who can
Pass Without Trace, at will, instead.