Don't quote me on this, but I recall reading from official channels that the last Debian version without mandatory systemd is going to see its support period indefinitely extended for a long time. Good luck! :)
If it's anything like the squeeze LTS experiment it's not going to be suitable for a number of people. There are a number of things they've been forced to abandon for various reasons.
And per the above experiment, it's not something you can depend on, not something you can build your plans around.
And per the above experiment, it's not something you can depend on, not something you can build your plans around.