I do think it would be a shame not to finally have a definitive release which includes the SLV. I know it has a lot of detractors because it makes an already languid film even longer, with quite a bit of redundant dialogue. There's also the Kirk spacewalk scene where he's wearing the wrong space suit.
But it's the first version of the film I saw, and I suspect many others are in the same boat. I'd love it to be represented on the ultimate UHD Blu-ray release.
For me, the SLV is easily the best cut of the film. I actively prefer the slower, more contemplative pace; additional footage like the “Spock cries for V’Ger” scene add a lot to what’s already a multilayered film; and keeping “We all create God in our own image” spoken onscreen is absolutely essential.
The original theatrical cut that everybody seemed to despise for decades is for me a very good second-best — it may not have the added stuff I prefer in the SLV, but it’s still perfectly solid.
I actually find the Director’s Cut the weakest of the three (which is a relative term — I don’t dislike it at all, I just prefer the other two).