Yes, it's obvious.

Ryouga is Doctor Who.

No he's not! 

Obviously, he's the long-lost SON of Dr. Who. Hmmm. Ace meets the Nerima
gang ... @_@;

I wouldn't put the Doctor through such trouble as making Ryoga his sone.
Now, he could pull of being the son of Susan (the Doctor's granddaughter)
Still, I don't think I could stand a warm reunion scene between the Doctor
and Ryoga. (of course, Ryoga probably would not be able to find the meeting
place the Doctor sets up.)

Do you think Ace could stand up to Nerima's finest (for like of a better
word) I bet Ranma could kick Ace's @ss anyday. You think Anything-Goes
could beat out Vanusian Karate? 

James