Personally, I like the Definitive Edition for some quality of life improvements like walkable farms and some minor enhancements on the interface and pathfinding (although most of the time it is still irritating), the graphics are also very nice. Though I must admit, the classic isometric and pixelated graphics of the original AOE and ROR are so vibrant, colorful and just cute and detailed for their time that they always get me.
I also prefer playing the classic Granary campaigns and the gems of the legends of old like Andrea, Ingo, Rich Parker, Imhotep, Gordon Farrell, FireLegion, Gumble, The Rasher and Fisk on the original 1997 game. The eye candy and the graphics simply don't transfer well to the Definitive Edition and the AI encounters issues that make the scenarios almost unplayable on the new version. And the overall feel and wish of the creators were to play the campaigns on the legacy game. So, in conclusion I love both versions, but the classic game has a special place in my heart, purely for nostalgia reasons.

Wow did I get included in someone's list of legendary designers?