Seriously though, I am not really sure how I feel about this. While systemd obviously has benefits, I just can't shake the feeling that it goes against the Unix paradiam. But then again, I also prefer xterms and a window manager over a desktop environments like KDE, Xfce, and Gnome, so maybe that explains my mixed feelings.
Very glad to hear we have a major binary distro like Debian committing to init system flexibility this strongly. I just hope it's true. The people who are hesitant can experiment and stay where they are for now, moving only when it's actually desired rather than forced.
it's very unlikely that SysVinit will continue to be supported, because writing init scripts for SysVinit is hard work, and if it isn't used as the default on Linux they'll rot.
I'm not in love with sysvinit, I just don't think systemd is the best option. It clashes, at least with my views on simplistic system design philosophy. OpenRC and FreeBSD's rc seem notably better than both systemd and sysvinit to me.