I haven't read the entire thread, but if I understand the OP correctly, then I think this is known by some of the more knowledgeable people. Just not discussed much these days. The main point as I understand it is splitting your stake means minting some POS blocks doesn't significantly reduce your chance of minting the next blocks.

For example, if you look at Balthazar's (Novacoin's developer) formula below, he already implicitly assumed this.
https://bitcointalk.org/index.php?topic=289946.msg3104704#msg3104704

That post is also very illustrative of the challenges POS systems face.