Y'all are too easily impressed lol. Yuris' character is weak, so far. I'd prefer more female cannon that is good rather than just "one more for the girls."
Roshi's stuff was, again, asinine. It's really cool, that battled Cell and Buu, and has trained all day every day, can be easily taken down by Roshi. Hell, why was he hiding all those amazing powers when Nappa, Androids, Cell, Buu etc? Maybe he just started training after Buu and magically leaped ahead.
It's plot based reasons, nothing more, so he can actually be in the Games.