I used to love that game but once Age of Kings came out I couldn't go back to it. The UI and some other mechanics are too limited in the original game vs the sequel. It just seemed like an all around better version of the same game, so AOE1 never pulled me back.
Does this "Definitive Edition" add features from AOE2?

I really enjoy the second game in the series.

I bought the Definitive edition and have really enjoyed it but I have yet to try the first one.

AOE:DE looks good and even though I have more fond memories of playing it I still return to the second one because of all of it's quality of life improvements in commanding your units. Hopefully this same level of control has been added to AOE DE but I don't know and have not done any research on it.