Sounds good to me. Anything to break up the meta. 90 seconds, more, maybe even tell the next point as soon as the active point changes. "A has become active. D will become active in 200 seconds." Good for vets, good for nubs.
What do you think about the spawn and point layouts? I pretty much put them in a symmetrical pattern, then checked out the places they landed. By happenstance, they all looked great for various combat situations. Moving them in further allowed for interesting corner spawns, keeping combat close and utilizing the never-used corners of the map.