I think basing our system on DPOS is a positive thing as it has proven to be one of the most influential, stable, and secure systems we have seen.
I suggest to analyze the issue described in
https://bitcointalk.org/index.php?topic=913075.msg10184529#msg10184529 before moving further.
Or set the security limit to 67 delegates instead of 51 until we get a formal proof that 51 is indeed enough.