That's a trade-off I'd be willing to make though given other advantages git offers. I wonder how mercurial would fare on that regard (possibly enhanced with a bespoke extension). Not that there's any reason for your tooling to change since it fits the bill so well :)
Anyway for archmac I went the boring way and stuffed everything as subdirs inside a single monorepo as I reckoned it'd just be easier for contributions. Definitely not the same scope as Arch Linux though.
FWIW there is a move towards git in Arch, which is happening slowly and I'm not sure what it'll end up looking like (probably 1 repo per pkgbuild on a custom git server, just like the AUR works right now). I was mostly talking about why svntogit looks the way it does :)
I often think about this issue of monorepos... git is such a wonderful tool, but the problems of subrepos and monorepos comes up so often it's surprising there isn't a definitive answer in git.
