It's hard to say what those changes will do. The rounded edges probably won't do anything, so no harm there. Changing dimensions is another story though. The cabinet is tall enough it has standing waves in the bass range. It was designed with Helmholtz models and double checked with Martin King's programs to ensure driver and port placement were optimal to reduce standing wave nodes.The two π tower measures and sounds very nice as it is. If you change something, I'd suggest measuring the modified speaker to see what you end up with.
To tell the truth, the biggest thing that affects response of towers or stand-mounted speakers isn't cabinet reflections anyway, whether internal or external. The biggest problem is outside the box, it's floor bounce.