Is there a way? I'd like to get some pointy roofs for a steeple.

It's two buttons, actually. There is one that affects every roof section by the same amount, (As well as adjusting the curvature of a pagoda roof) and another one that lets you adjust individual roof sections in a manner similar to adjusting the height of a wall hanging.

Nah, what I mean is pushing the roof slider beyond its current maximum level.

Oh, a roof multiplier hack. Nope, never seen one. But it's an intriguing idea.

I've gotten some pretty tall roofs by sliding the overall slider up as high as it would go, and then adjusting the bit that I wanted even taller with the individual slider. (And then adjusting all the other roofs back down with the individual slider... which is why it's more of a proof of concept idea than something to use on a large lot with a complex roof.)

Edit: and apparently that has been fixed along with making foundation basements harder to manage...

I know Awesome Mod had an individual roof slider function before EA decided to give us one. I have no idea if it still does or not because it's been a while since I used it. It wouldn't surprise me if that was the roof slider I was thinking of.