The spout should taper all the way to the opening. This keeps a pressure increase to the spout- if it widened, then there would be a pressure drop and a possibility of gurgling.
The spout twists in the direction of clay twist (if thrown) during the firing- so if it's cut at an angle, that angle will twist a bit and not be level. Many potters will compensate a bit when they cut the spout.
The "fatal flaw" in a teapot is when the spout lip is lower than the level to which the pot will be filled so that when it's filled up, water is coming out the spout.
Porous clay normally implies low-fire, so find out if she's doing stoneware temps or earthenware temps.
Any potter could go on and on about teapot design. It would be best to get a decent book- Robbin Hopper has a few great texts on functional pottery design that I like.