For the Bucks this fits exactly what they want in the Giannis package. They get a super exiting piece in Amen Thompson and valuable first round picks. If you think that Amen could one day become a top 10 player in the world and be a true #1 scoring option on a championship team this would probably be a little too big of a haul for Giannis. Me personally I think Amen's ceiling is to 20 - 15 player in the league unless he can develop a consistent jumper. In that case you are giving up a very reasonable package for a two-time MVP.
For the Rockets even though the more popular candidates for trades are Booker or KD, I think they should and will go after Giannis. I don't think Booker can be a true #1 for a championship team and you would have to give up more than what he is worth because the Suns aren't shopping him right now. KD is too old, and he came out saying he wants to go to the spurs and it's only a matter of time till he goes there. If you are worried about the spacing issues that Giannis might bring, I think it's fine. The rockets were a good offence with bad spacing last year. (total offence not half-court offence) I still think Sengun can develop a three-point shot and Giannis has a mid-rage game now as well. Plus, the Rockets can add shooting with other trades or the free agent market.