010101 I think the best visual solution is to keep badge on top as was, in the core adding your first template that is what I'm using as default (vertical) adding also the line to hide if more than 5 badges.
Will be maybe less nice made the badges down as default, this means change in some way how Flarum burn and I think badges are more nice on top. I tried all solution and to me look the best: how was but with some fix needed.
Anyway, any decision if an extension will be made will be not a big issue just a decision that will give user preference... means move the badge from top (the best graphically) to down.
OPS I read wrong or doing confusion.
So yeah, probably in core for now, leave badges as-is, close down my pull request if others agree. And then an extension is worked on.
Leave the badge as is now means on top? Currently here badges are down for testing so I'm confusing how will be the standard. If will be keep on top, that looks the best to me, maybe will be useful ... aww.. hard.
I think your first CSS on vertical should be the default because fix issues and never change too much how Flarum is.
Extension maybe can allow badge down or circle.
I know this will require more work compared to leave the badge as is now... but the important thinks is maybe have the best possible default badge in core.