Yeah the shift click thing is weird, here's how i've been making smooth roads up hills:
aim straight down, walk sideways, flatten ground. As you go up a hill it makes for quite an even slope, and if you turn your aiming slightly ahead or behind, you can adjust it even further. It's all about aiming right at your feet though, anything further out feels too weird.

As for flattening large patches of ground.. it's the same drill as before the patch. Hoe and Pickaxe the ground until it's flat. Shift click method is interesting, gotta get used to it.