The Ramma outlines his intent in his forward to Toras Chatas. He says he is writing a compendium of the modern works upon whom the practices of his times were observed. He says he is not competing with Rav Yosef Kaaro who's work spread all over the world. He is simply pointing out the places where if someone would open the Shulchan Aruch for a ruling, he would undo the minhagim that were practiced in those countries.
This seems to be in stark contrast to the Reb Yosef Kaaro, in his forward to his Beis Yosef on the Tur, who although he did bring modern sources when the classic ones did not discuss a subject, his express intent was a return to the basics and uncovering sources from the three pillars of halcha, the Riff, Rambam and Rosh. He limited his halakhic ruling to simplistic basic laws.
These differences show in their respective works as the Beis Yosef appears as a 'lamdan' discussing and clarifying, and the Ramma ends up as a 'milaket', a gatherer of ideas, without getting as much into foundations and theories.