Urgot would be far more balanced as a Magic Damage AP Tank
Than an AD Bruiser Tank Marksman monstrosity
Same general playstyle, healthier builds and balance paths, already kinda looks the part anyway.
Ranged AP Bruiser is actually pretty damn unique. I can't think of very many that fit this. As a ranged AD bruiser he is outclassed by Jayce in every way and as an AD Caster Carry he is destroyed by Graves/Sivir/Ezreal/Lucian etc.,
Give him an entirely unique niche by just switching all of his stuff to AP and Magic damage.
Make his new passive lower magic resist on the target and deal bonus magic damage on-hit. Make his E magic damage DoT + slow + greivous wounds instead of shredding Armor or MR. Give his W Mana and Health ratios instead of AP and possibly even give it Armor + MR when activated instead of slowing on Q and Autos.
also look at him. He already kinda has the same motif as Maokai and various other AP tanks. One look at him and I go "he must be like Gragas and Maokai, an AP caster tank right?"