Rico, the corners could be partially filled in, although we need to provide suitable access for the emergency services. I think the only tweak I would consider would be to move the plant compound to the corner of the RDS / SS (removing the mound) and enable that corner to be filled in, albeit maintaining a route through on to the pitch for the emergency services. That being said, this would only be to the benefit of a few seat which isn't realistically going to make much difference. It might also be a struggle to unify the changes in heights between the main stand / merkie without providing terrible sight lines.
I'm guessing, but if we did do the wave form stand, depending on where it started, the amount of structure required to provide little benefit would probably be the reason why you wouldn't do it. Seat kills would be quite drastic.
Tom, as a side note, are the accessible seats pitch side or at higher level? If the former, I'd presume we'd lose a few more seats as it's generally preferred to have a mixture of the two options available.
Again, great work Tom