My Ideas on a new AP JG item (REUPLOADED)

NOTE: I'm not saying we should replace Runeglaive, but AD junglers have 2 JG items technically, so AP junglers should too. (Not too worried about tanks atm since they don't vary too much when it comes to Cinderhulk)

So I had my own idea for a JG enchantment for AP Champs that don't really benefit from Runeglaive's spellblade ability. So here it is:

NEW JG ENCHANT: Warlock enchant color: teal/cyan builds out of: JG item + Fiendish Codex + Amp Tone Stats: 80 AP %10 CDR 250 Mana Unique Passive: Spellbound: Every time an ability deals magic damage (excluding lane minions), you get 1 charge. At 10 charges, the next ability will apply a %40 slow for 1.5 seconds. At 20 charges, the next ability will consume all charges and stun the target for 2 seconds and deal magic damage equal to %20 of the user's AP. It will also deal lesser damage to surrounding enemies in a shockwave.

Also, The stacks will be 15 and 30 for AoE and DoT damage, or maybe have the damage value be halved (10 stacks = %40 for .75 seconds, and 20 stacks = stun for 1 second and deal %10 AP damage)

It's something I thought up while thinking how the preseason is somewhat pushing mid-lane mages into the jungle, yet Runeglaive doesn't really offer anything good for them. I do have some considerations of some of the things that it does, like should enemies be able to be hit by multiple shockwaves, or whether or not the shockwaves will trigger the stacks itself. Personally, I'd LOVE to see the return of JG Karthus myself. Riot feedback is appreciated!