Making the new OPs SM require (72) and drop (75), and HM's require (75) and drops (new high level gear) is not unreasonable at all. This just forces people to progress as follows: Ding 55, FP's, SM TFB/SV, HM TFB/SV, then either NiM TFB/SV or New OPs SM, New OPs HM.
That seems very reasonable to me. Yes only the most geared teams will be able to compete in the new HM's quickly, but it forces a reasonable progression. Otherwise I could take a fresh 55 and have them running the new Operations on HM in 3 weeks.
IF for some reason the new HM's only require (72) gear then the new operations are not a progression based addition to the game. They would stand much more as equals to TFB and SV instead of ahead of them in a linear content POV. I fully expect the new SM's to require (72) gear. I hope, I hope, I hope.
Oh I'm not saying I personally don't think its reasonable to require 72s for SM if we're talking progression. BUT the general attitude with BW so far seems to be that they want casual players to be able to access SM (hence STORY mode). A casual player has a difficult time getting 72s. And if they didn't require 72s for SM I just couldn't see them jumping to requiring 75s for HM. Again, this isn't something I'm advocating, just something I think likely from their past releases.
I do like the idea a poster above had about one op being significantly harder than the other and requiring a higher level of gear. Meaning Dread Fortress requires only 69s for SM and drops 72s while HM requires 72s and drops 75s. BUT then Dread Palace SM requires 72s etc. In my mind, that would require higher gear to even access SM but would still be in-line with BW's policy of casual players being able to access SM of all ops. As much as raiders (I include myself in this group) want harder content, I just don't see BW restricting SM to a high degree, thats all.
EDIT: Though I do realize if only Dread Palace HM dropped the new tier, then we wouldn't have a complete set. So basically, I don't think there's any way to predict the new gear requirements. We'll just have to wait and see whats released