I Actually Like Smite on Laners
Other than the fact that some champions have become totally OP, smite has made is so that each lane isn't stuck with certain summoner spells
Top - Teleport, Flash, Ignite Jungle - Flash, Smite, Ghost Mid - Flash, Ignite, Heal, Exhaust ADC - Flash, Heal Supp - Flash, Exhaust, Ignite
Each lane is very limited in their choice of (successful) summoner spells. The majority of the summoner spells chosen and matchup-related or champion-specific (heal mid, ghost jung, anytime someone uses cleanse). Even if smite means you have to take flash and have no other options, it is one more spell that can be used. It opens up to new strategies and increases champion diversity.
NOTE: I am not saying certain champions are not OP. This thread does not have anything to do with OP champions. It is about how smite is helping spell diversity. As of now, some champions are OP with smite (or UP) and I'm not saying they shouldn't be nerfed in some way, I am simply stating how smite is now helping add more successful strategies in League of Legends
feel left out.
was only popular on top laners because both Challenging Smite and Cinderhulk were objectively way too strong, and now 
is only popular on AP 
because of a major bug (it applies spell effects when it shouldn't). A potential risk with jungle enchantments on laners is also that it would risk having them one-up junglers again: junglers typically have access to really cool bonuses and items because they're going to be behind in gold and experience for most of the game, and having laners purchase those juicy items on a regular basis would just put junglers back at a disadvantage. There might also be an issue with giving laners tons of jungle-related power, since that would also risk diluting the role of the jungler as a unique and powerful contributor to jungle control. More selfishly, I'm reluctant to see laners with Smite and jungle items because I know that means I'll have less jungle farm to work with, even though I could compensate by clearing minion waves in lane (that might not be an adequate fallback strategy when 
gets updated, though). There's a lot of potential for Smite to expand as a versatile, powerful clearing and objective control spell, but it needs to be done in such a way that junglers still get to be the kings (or queens) of the jungle.
