Suggestion: Have the spell "Jump" enable crossing horizontal (and/or vertical) climbing/grapple points (similar to the effect of "Spring Boots" or "Jumping Bean" or "Levitate Potion"). Alternatively, add a new custom transmutation spell, "Levitate", of any spell level, which enables this.
I do not think this would make exploration/ringrunning any less hellishly difficult or challenging for wizards; it would just make the gameplay more wizardly, flavorful and marginally more convenient.
Frankly I'd just be happy if jump worked consistantly.