I'm not sure if I understand you correctly, but it seems likely that both the SPS and EIP will end up being included and released with HF21. Adding in the EIP changes will take additional work from the core development team to build, it will take additional time and effort to test, and the more changes you include the more chances there are for issues to happen.
I don't think all of that is worth it for something that I don't think will contribute in any meaningful way to achieving the vision of Steem that I outlined in the post. That is why I would prefer not to do it and instead focus that time and effort on things that will get us closer to our goals.