goto Appearance tab
It would be great to have font size and align left, center and right options for posts.
This will give you align, but not font size. Font size would be pretty annoying, as it makes everything different sizes, one of the benefits of NodeBB is it's uniformed approach, one of the main reasons I'm glad to be rid of awful BBCode like [glow] etc.
NodeBB's aesthetics are very attractive. However, it would still be nice to have the option to size code. I do see where you're coming from, though.
@JonDoe12 It's doable, you'd just take someone entering
[font=8]text[/font] and replace the font bits with some css. maybe via span classes or something like that.