Secondary Rune tree

Wouldn't it make more sense that if you want to change the bottom rune of your secondary tree, you can just change it right away instead of having to pick both runes first. Like how does that make sense? If you want to change your primary tree, you can change the rune you want right away, but if you want to change your secondary tree, you have to first select the top rune, then the bottom rune... [zombie-brand-mindblown]

I hope this makes sense to you guys and you understand what I'm saying here (not a native english speaker :p)