Karthus Ultimate Adjustment Idea

Considering Karthus is a burst carry, his ult needs some fine-tuning to be able to function as more of an execute in order to fulfill its purpose as one on paper. Being able to use Requiem without fear of seeing "the one that got away" recalling with the tiniest amount of HP can be tilting. Here's my idea comparison with the current ult, plus damage values for 30 MR and 120 MR targets.

Current ult: 250/400/550 (+60% AP) 700 AP vs 30 MR + 500/2200 HP: 745.93 700 AP vs 120 MR + 500/4400 HP: 436.5

Proposed Ult: 200/250/300 (+20% AP)(+15% Target Missing HP) 700 AP vs 30 MR + 500/2200 HP: 636 700 AP vs 120 MR + 500/4400 HP: 461.25

Damage values are from a full AP build not featuring Magic Penetration

This is only an idea to help make Karthus a decent pick for the new season