[Rework Concept] Cho'gath, terror of the void

Maintaining an identity: Cho'gath has a few things which stand out to me. He gets bigger and tankier as he gains ultimate stacks (with no draw back), high damage skills while tanky, tanky while going full damage, and a serious mobility issue (especially compared to new champions.) The proposed rework (is not fully fledged out with ratios) attempts to maintain cho'gath's core identity while making him more competitive, have a non-linear play style, and have clear pro's and con's to his play-style.

Small Cho: Cho'gath now starts with increased movement speed at 0 ult stacks and has normal ap ratios, his current q and w have low cast times and small hitboxs to compliment this.

Cho With Stacks: As Cho'gath gains feast stacks he gains tank stats (add armor and mr to his current gained health) but loses movement speed. As Cho'gath gains ult stacks he gets decreased ap ratios but the cast time and hit box on his skills increase (thematically makes sense for a dinosaur/monster)

• Rework the passive to gain health and mana on hit once every X seconds. Small/no stack Cho'gath has a higher mana regain ratio and a lower health regain ratio, as he gains stacks this ratio flips. This promotes a squishy hard hitting mage versus a hard hitting in the middle of the fight stacked cho'gath.
• Feast no longer deals true damage (perhaps a cripple or a bleed) and no longer loses stacks upon death, instead loses a stack every X amount of time. (The timed loss of the ult gives a weakness window of someone playing a glass cannon Cho'gath in which they are slower and deal less damage and makes someone playing a tank style Cho'gath have to use the ult to maintain his tank status.)
• Feast now has less stacks (2-4 perhaps but scales much harder)

The proposed Cho'gath changes has kind-of a evolution theme to it as he evolves from a glass cannon hard hitter to a "wet noodle" immobile tank. These changes almost combine a Gnar or Elise form change concept with a Kha'zix like evolution theme. Would really enjoy feedback/additional ideas to this proposed rework.