Lets just git rid of smite as a summoner spell and put it on a jungle item instead

Smite would be an active on machete, talisman, and all their derivatives.

Epic monsters would be vulnerable to only a single smite from each team once every 10 seconds. If someone on your team smites it, it takes 10 seconds before anyone else on your team can smite it again; although enemy team can still smite it (once per 10 seconds)

Given the fact that junglers would effectively have a whole 'nother summoner spell more than they have now, the jungle items can be focused more towards the utility of smite and away from raw stats. Different jungle items can make the smite active more versatile; usable in other situations (currently have a little bit of this, but could double down on it)

The jungle items would passively make you much stronger against the jungle monsters, to the point that past level 5 or 6, trying to doing more than one camp without at least upgrading machete or talisman would be practically impossible.