What if riot added alternative build exclusive mechanics?

What i mean by this is that champions are given mechanics on their existing abilities, or whole passives, which have extremely low base values or none at all, but scale with a stat which is unique relative to the rest of the kit.

So say a champion like Keld. Who only scales with AD, Atk Spd, CDR, and HP. What if you added in a slow to his initial Q which slowed the target, but only existed if you had AP (maybe even make a threshold so that random runes or masteries don't enable it). Or a passive on his W, which increases his auto attack range while unmounted, which increased base on how much bonus mana he has.

Obviously these mechanics wouldn't exist unless you were doing a non-optimal build, though, they would function as alternative options which players could utilize to cleverly overcome situations which the primary mechanics of the champion might struggle with.

It's similar to something people have suggested to do in hearthstone, where some spells be given secondary effects which scale with "spell power", as a means of including new mechanics into decks, by swapping good cards in the deck for weaker cards which change how the deck plays. You lower the average power, increase an alternative specialization.

In a sense, it'd be like adding inefficient situational mechanics to champions which allow players to exchange power and utility, again inefficiently.