True it doesn't necessarily mean that he's stronger than Piccolo, just that he probably is.
As for Piccolo, everything indicates that he got soft after the Cell Saga.
Buutenk's blast looked big enough to hurt Gohan, at least in the anime. I might go back in the manga and find it.
@phantomrant: The dude trained seven years, so i'm sure he's stronger then a super saiyan by the Buu Saga. People just don't want to accept the fact that Tien is probably stronger then Piccolo by the Buu Saga, due to Piccolo's lack of training the seven years and giving up his rivalry with Goku. Also Buutenk's blast was a little big for fodders. Buu just loves to overkill.
@flashback180: Depends on the size of the dinosaur. Something like a Velociraptor would be easy for anyone to cut with a Gantz sword. I will give Ryouta's bombs the benefit of the doubt though based on the info you provided.
Don't know about Ryouta, but as long as Kurono has his suit he has way higher durability then Takashi and the Gantz sword can cut dinosaurs in half with one swing.