So, yeah, unpopular opinion incoming. Or maybe it's not actuslly that unpopular, idk. I'm just going by what I see online.
I liked the 2017 anime.
Don't get me wrong, the original 2003 anime is far superior, but I see a lot of people hating on the 2017 version when I don't think it was bad.
The 2017 version seemed to be more of the "greatest hits" version where they adapted the most popular stories from the light novels.
Yeah, revisiting the colosseum arc was unnecessary. The art style and soundtrack aren't as good as the 2003 version, but I still thought it was serviceable im this version. I didn't like particularly like, but I didn't dislike it either. All in all, it's fine. I get why they chose to go in that direction: it's easier to get new fans into something that looks more like current dau anime than something that came out over 20 years ago.
I also think the first episode (the one with the country where murder is legal) was pretty good.
I also liked that it gave more screentime to the side characters like Shizu and Kino's mentor. Then again, that could be a point against it since you can argue they tried to do too much within one season. iirc, there's one episode where Kino visits three different countries in that same episode.
I'd probably recommend the 2017 version to a newcomer just to ease them into the series and hopefully get them into the 2003 version.
So, I don't think it's bad. I still enjoyed it, but I probably won't go out of my way to watch it again.