I believe the future diamond interchange is temporary. At least, I hope it is. After all, the Gilcrease west of M.L.K. Jr. Blvd. is a two-lane highway with at-grade intersections that will likely become a four-lane freeway/tollway in the future.
I hope you're right. But we're dealing with ODOT and the OTA, so who knows what it will eventually look like. There is a precedent for this, as the current Gilcrease/Tisdale at grade intersection is (supposedly) a temporary setup.
The road that is currently signed as the Gilcrease Expressway between N 41st W Avenue and the LL is a temporary road. I don't know what the final configuration is going to look like, but I expect part of the temporary Gilcrease will be buried underneath the freeway Gilcrease, and part of it will remain in place as a frontage road.
Here is a PDF file of ODOT's plans for the Gilcrease/Tisdale interchange as of 2008. An ODOT contact sent me three PDF files of this interchange, and I fused them together into one PDF file. 2008 was 14 years ago (My, how time flies...) and the plans could have changed significantly (especially since the OTA will be involved now), but this is the original plan for the interchange.