So, what do you think the results would be if all of Garen's abilities that have a ratio, were given an AP ratio as well?  Let's say, for the sake of argument, Decisive Strike gets a 1:1 AP ratio and Judgment gets a .5:1 AP (total 3:1 AP) ratio.  Maybe put a 1:1 AP ratio on Demacian Justice even though it doesn't have one naturally.

Just for one day, maybe on the PBE, I wouldn't mind seeing the mayhem caused by such unusual builds.

Imagine him pure AP with DFG, Rabadon's, Rylai's, Abyssal, Ionian, Zhonya's.

587.5 Ability Power, 50 Armor, 45 Magic Resist, 500 health, 30% cooldown reduction from items alone.

Assuming no AP runes or masteries, his Q would hit for 130+161.7+587.5 =  879.2 physical.

His E would hit for 120+127.05+293.75 = 540.8 physical damage per second. Total damage for a full spin would be 1622.4 physical damage.

And his ult, if the AP ratio was given, would deal 525+587.5 = 1112.5 magic damage base before health scaling.

His Spin would also apply a 15% slow, and his R would proc a 30% slow.  His burst cycle would deal 15% target's maximum health in magic damage(DFG), followed by 2501.6 physical damage in approximately 3.5 seconds(Q+E).  Another half second later would see another 1112.5 magic damage (R), which if fast enough, could catch the tail end of DFG's damage boost for a total burst of 1335 magic damage on his R without including health scaling.

I suppose, since he'd have almost no ar pen or mpen, these values would get harshed by at least 50%, that's still a nice amount of burst damage for a full cycle.

Of course, with masteries this changes quite a bit, but since there seems to be an impulse to run him with tank masteries, it would be more survivability rather than offense.  However, if you went heavy into the offense tree, you could make this even worse with some ArPen & MPen, not to mention bonus AD & AP.

Maybe I'm wrong on this, but that would be hilarious for April Fools'.  It wouldn't be incredibly viable, as it offers no crit (which Garen makes fine use of), and no armor shred or magic penetration, but hey, its supposed to be a joke build, right?

AP Garen for April Fools'.