Ŧhe only thing i want to maintain is that taking Smite in lane should remain a viable option. An odd pick and unoptimal to be sure, but still viable. Either that, or i think they should tweak other summoner's spells around to have similar item-building mechanics as Smite currently does.
If linking a Spell to the wildly varying 'Role' of junglers causes issues in the jungle, i feel like linking a Spell to each 'Class' in the game might actually be a good thing.
Ignite on Assassins, Teleport on Tanks, Exhaust (linked to the Sightstone item?) on Supports, Ghost on Fighters, Flash on Marksmen, and Barrier on Mages. Of course, that's going with the current spells only (i think the entire roster should be remade and re-pimped), and most could easily be swapped around, but the important thing would be this; Only one Summoner' Spell 'upgrade' item could be used on any champion at any time, and those items would be restricted by what they build into (Say Hecarim couldn't benefit from both Teleport's tanky upgrade and Ghost's damage-y upgrade at the same time), but would allow Smite-like flexibility to the other spells.
P.S.; If Sightstone were to be Linked to Exhaust, Sightstone would still be buyable by anyone, but it's fancy new upgrades only to the user of Exhaust.