I cannot decide yet... Hyrule Warriors is one of my favourites of all time... Spent like 600 plus hours across Wii U and Switch.
Definitive Edition definitely has more content. But I don't think the base game when it released had more content than Age of Calamity does now. Age of Calamity has made me love Breath of the Wild even more (its world, its characters). I'm actually enjoying some aspects of Age of Calamity much more than Breath of the Wild (Story presentation, combat, MUSIC, weapon system)... But that is a bit off topic...
I think Hyrule Warriors Wii U (without any of the extra content) isn't as whole of an experience as Age of Calamity's base game. I still have yet to finish Age of Calamity, but I can confidently say it is better in that regard... As of now, the edge goes to Definitive Edition, but that may change once I finish the base game and if it gets any substantial DLC.
I do love both games very much, and am very happy to see this sub-series do so well.