I really enjoy this set! The novelties are super clean.
However, I'm really not a fan of the lack of 2.75u, 2.25u, and 2u spacebars in the 40s kit. To have to buy base + 40s + spacebars in order to fill one split space 40s board is incredibly expensive, and exactly what prevented me from buying either the 40s or spacebar kits in the Sumi buy. As a 40s user, I would much prefer a trimmed 40s kit with some spacebars, rather than a large kit without then needing to buy a space kit. The R4 1u, Shift, Enter, and accent Enter could be condensed into one generic 1u "send" key. The two R3 " keys are dupes, if I'm not mistaken? The 1u R2 Backspace key can be removed as the Delete key in base fills that role. The R4 1.5u Shift can go as well. As far as I know, only the UT47.2 and Whimsy (still in IC) use this key, and this can be easily filled by some of the mod keys in the base kit. With these changes I think it's plenty possible to fit the split spacebars into the 40s kit. Needing to spend an additional ~$80 to cover a 40% board is unacceptable, even as far as GMK sets go.
As for novelties, some 40s love in there would be nice too! R2 1u black box key, and a 1.75u, 1.25u, and 1u enter would be awesome. If not all are possible, then consider my list my priority list as well.