Not really. Bicycle "rake" is a measure of distance, and horizontal distance at that. Adjectives like "steeper" are reserved for use with angles, not with distances. Adjectives like "shallower", even though they can be used with distances, are usually reserved for depth-specific distances (like depth of a socket, blind hole or groove). Neither is naturally applicable to rake.

Rake is measured forward from the steering axle to the wheel axis. Which means that on a traditional bicycle rake is a positive value. Greater rake means that the wheel axis is placed farther forward (more trail, more stability). Smaller rake means that the wheel axis is closer to the steering axis (less trail, less stability), and can even become negative if the wheel axis is behind the steering axis.

"More rake" might not sound too formal, I agree. But it should not take a rocket scientist to figure out that "more rake" means "greater rake", "larger rake value".