There is some logic in waiting for Cubase 10.5.
Now that Nuendo has come into step with Cubase, it remains to be seen how Steinberg handle the release cycles of the two products going forwards. Eventually Nuendo might release at the same time as, or a relatively short time after, the corresponding version of Cubase; nobody knows yet other than Steinberg, and Steinberg are understandably not talking about plans that far into the future. What happens may well depend on how much Steinberg care about Nuendo being seen as a Cubase superset (with one omission that doesn’t matter for most people - Nuendo does not have VST Transit) rather than a product with its own distinct brand and identity.
Cubase 10 has been out for six months, Nuendo 10 for just a matter of weeks. As the additional functionality of Nuendo over Cubase Pro is almost entirely for video and game workflows, video rendering is quite clearly a core feature for Nuendo and it makes sense for the feature to land in Nuendo first. Even after the price cut for Nuendo 10, Nuendo is still almost twice the price of Cubase Pro once the current Cubase sale ends. Video rendering has always been promised as part of Nuendo 10, albeit not at release, whereas it has never been promised for Cubase 10. (I think I’m right in saying that the only feature announced for Cubase 10 that has yet to release is ARA2 support).
I will be surprised if there is a paid upgrade to Nuendo 10.5 as little as 6-8 months from the release of Nuendo 10, unless the upgrade cost is minimal.
At least now people have a clear understanding of what is happening.
If early access to video rendering is important to you, wait until Nuendo 10.2 is released, then crossgrade to Nuendo 10. However, Steinberg is not forcing those wanting video rendering to crossgrade to Nuendo so long as they are happy to wait for Cubase 10.5.
Cubase 10.5 is likely to release with mature video rendering, as the code should have matured in Nuendo. Those already on Cubase 10 will have to pay for a “.5” upgrade, but Steinberg’s upgrade cost for such an upgrade is usually fairly modest even if you upgrade early rather than wait for a sale. Those who are not already on Cubase Pro 10 can buy a version upgrade to Cubase Pro 10 in the current sale and leave the activation code unused until the grace period for Cubase 10.5 starts which should, if Steinberg stick to their historic policies, result in a free upgrade to 10.5 on its release.