Mechanical Impacts of Altering the Flavor of Magic

Suppose I want to alter the system of magic. Let's say I'm going to leave divine magic as is, but arcane magic is completely removed, replaced with elemental magic based on three elements which have a paper-rock-scissors relationship (air sprays water; water erodes earth; earth resists air). From a flavor standpoint, this elemental magic is considered arcane magic, but that's strictly from a flavor standpoint. The vast majority of things which would be called arcane magic simply do not exist; no teleportation, fireballs, etc (except as done by other power sources).

Assume as well that the other power sources, while available, are rare enough that the exceptions to the lack of typical arcane magic tropes aren't obviated by non-arcane doppelgangers (so you might be able to teleport using shadow magic, or deal fire damage using divine magic, but in general the game world assumes that it's nigh impossible to teleport and nigh impossible to wield magical fire.

The initial thought I have is that this should be fairly simple to implement. I just choose not to use enemies whose powers don't fit in this new system, or adapt the flavor so that they do.

But then I think about it more, and I worry that there might be implications I'm missing, both from the absence of arcane magic tropes and the addition of relatively common elemental magic. For example, energy resistance is probably not nearly as valuable in such a setting, since most energy damage is dealt by traditional arcanists.

Can you think of any other issues?

How do you cast Hold Monster? Well, I suppose you encase them in a block of stone. But now you need to alter the save type/defense targeted. (Are you talking about 3e DnD, 4e DnD, or some other system here?)

I have to say 2e Dark Sun did this ... poorly. In 2e, all clerics worshiped the elements (or, more to the point, go their powers from them), and if you weren't a druid or a templar (evil!), you picked one element. Unless you picked fire you were going to suck at combat, at least until they added some new spells via splats (air lens was a cool one, for instance).

Even so, they did get regular "cosmos sphere" spells (healing, etc) but only up to 3rd-level. So past that point, retire your cleric and play a druid. *Sigh* Not that druids were bad, but some people didn't like them for RP reasons. (Please note, as an aside, I did not like the 2e cleric. In fact, only high level 3e clerics, or 4e clerics, seemed to have any role in the game beyond heal bot. I've already drawn up more 4e cleric-type NPCs than I did in the previous two editions combined, and I DMed 3e for years!)

IMO, you would need to look at every spells and/or power and determine if the game can do without it. If you should keep it, then you need to reflavor the spell/power. I personally could go without 3.x-style teleportation, but I would be very upset if spells like Command and Cause Fear were taken away. I don't know about Command, but Cause Fear could be using wind to push the victim away (it would no longer be a fear effect, and called something different, but the PCs could still use it).