@Rod...
1. No one is saying LTS does not have bugs, the point is to fix and minimize bugs by not constantly rolling out new features that can cause new bugs or reintroduce bugs.
2. This is the reason for LTS, you dont want to add in "new" things (other than bug fix code of course). Patching existing code to fix an issue is much less error-prone than adding in something completely new.
3. .Net fwk is stable and is not getting new features added to it, it's bug and security fixes only. .Net fwk 4.7+ has no EOL date currently and I am sure Microsoft is going to continue to support it for the most likely very long future. Changing from one .net version to a completely new .net environment that now runs on a completely new set of operating systems is of course adding in 100s if not thousands of new variables.
4. Possible, but pretty unlikely. 99% of the bugs we've encountered with SM have been SM-related, not .net, not a 3rd party app, not some 3rd party modules.
I dont see an issue with having an LTS build, a bleeding edge "stable" build and a further looking beta build. I understand it takes more manpower, time and money to support this, but it's beneficial in the end for everyone, especially ISPs and larger enterprises that want bug fixes and stability over shiny new features.
Take for example the current new build (8965) has a fix for a bug we reported with EWS dying (with eM Client) when downloading certain messages with attachments. In order to get this fix, we have to risk installing a massive build with new features, changes and other fixes. The fixes are fine, but what issues will now come out from all the changes and new features. The risk to reward is too high.