Zeke's has so much potential! Here's my take

Zeke's Convergence looks like such a great item, I'd love it if it were cooler.

As of right now Zeke's gives ADC 30% burn damage (magic) on their autos when the item bearer ults factoring crits but no other modifiers. It also gives the item bearer a little zone around them that does some damage and slows.

The burn used to be 50% and was un-interactive and really overpowered, so they nerfed it to 30% but I don't think that was most effective

MY PROPOSAL:

The zone's radius gets increased by 30% (effectively increasing the area by 70%) and maintains the 30% slow. The damage the ADC does in auto-attacks with all modifiers has 40% of it converted to a 1 second magic damage burn in the Zeke's zone. Attacking someone within the zone within grants the ADC 50 MS for 1.5 seconds (mini Sivir passive). The stats stay the same.

This makes an item based around the Zeke's zone, it'll provide great effect when used right, especially in teamfights. Also it keeps the item from champions like Lulu, who just want to buff the damage.