It's early yet. Early silicon, early boards and early Bios revisions. So things may change or be proven/disproven. But the i5 and 8~series i7 don't appear to have the same overclocking potential of the LGA1366 9** i7's. There's some theory floating around - (...which passed my common sense filter. NVM the usual high dose of partisan stupidity that some pawn off as knowledge) - that the difference may be related to how the integrated PCi lanes interact with the base clock. But I don't think many/any~one outside of Intel fully understand why just yet. There's a lot of really smart peeps out there, though, so I'm sure we'll hear the real reasons sooner or later.
It could simply be that's part of how Intel want to position the chips. i5 and 8~series i7 for more mainstream usage, and 9~series i7 for enthusiasts and heavier duty apps.
On a related note: I know there's at least a couple employees who stick their heads in here from time to time - Perhaps they could relay the suggestion to the marketing department their message/branding is muddy and hard to understand.