I loved XD, and Colosseum is great too! I personally prefer XD, so if you like the first one...well, I hope you'll get just as much enjoyment if not more from XD!
I would die for a sequel, or even a remake with updated mechanics, but I know it would be lackluster. There's something about the animations in Colo/XD that gives so much life to the pokemon that I just don't feel from the new 3D models' animations. From what I recall, Colo/XD were made in part by another studio? And I really think having that outside source helped them push the models and main gameplay elements to their fullest potential!
XD is definitely my favourite "spinoff" pokemon game. Hands down. It holds up surprisingly well even now, which is hard to say for games! The physical/special hard-set types is my biggest gripe (rip Mightyena, my beloved), but the rest? Phenomenal. 12/10 would play these games forever, and would play countless more!