The alterations to arcane spells tend to be fun and interesting. So, for every impeded spell a wizard casts he might get an enhanced spell. Or, depending on the plane any sort of alteration is possible. The divine caster just loses some caster levels. Doesn't seem like a great tradeoff.
Well, under 3E and 3.5E all spells get assigned schools so you can treat them all equally if you like.
Still, at least philosophically, there's a reason for this difference in how they're treated. Arcane magic operates off of the rules of the Multiverse and how they're applied in the various locales of the Great Wheel. Thus on certain planes the physical and metaphysical laws are just different, and arcane magic is affected accordingly.
Divine magic on the other hand is a deity focusing its will through an intermediary, in this case a cleric. Under the original Planescape rule the deity's ability to make its will manifest is dependant upon how many planes its will is diluted through en route to the intermediary. Under my suggestion the deity's ability to make its will manifest is dependant upon how philosophically similar the plane the intermediary is residing on.
It makes a lot of sense when you take into account spell keys and power keys. Spell keys are arcane formulae that compensate for a plane's altered physical and metaphysical laws. Power keys are literally a way to mainline a deity. Each has a roleplaying aspect that can be fun to explore. For example, you'd imagine that the powers-that-be of a given plane would be able to
sense a power key attuned to a deity whose alignment is opposed to them. It would irritate the very fabric of the plane, and they'd take it very seriously because it's a way for their enemy to force its will upon the plane in a way they would not normally be able to.
So think of the various circumstances that would create these keys. Spell keys are pretty obvious as they can be researched given enough time and resources. Power keys though? You almost have to look to the fiction for examples on those. For instance I remember there was a Forgotten Realms novel where Cyric forbade mentioning any other deities by name on his plane because doing so allowed them to intercede upon his affairs. Things like that are fertile ground for developing a mythos around power keys.