Rooting really isn't the reason I am getting this, so I don't consider space for that to be crucial. Also, I do all my music and movies through plex, so no need for local storage. And all my essential apps on iOS account to 1.5 GB. Thinking about it, I don't really need the 16GB. But maybe I am just talking like this to talk myself into saving an extra $50
You know yourself better than I do and if you've used a phone with 8GB and managed then go for it
It's just a smarter move to get the 16GB to make it more future proof and in case your usage changes. I guess it depends on how long you plan on using this phone for.