I think you have a much more stylized view of what a side of a debate is than reality suggests is the case. Creating an implementation for a side that wasn't already rallying around one would just exacerbate the differences in opinion on that side and fragment it into multiple smaller sides.

There aren't actually two sides of this. There are only in the scope of systemd vs everyone else (just because systemd is something that is pushed as THE solution).

There are multiple solutions that all have their supporters. And we generally actually get along and work together pretty well. BEcause we don't think that one solution is necessarily better than the other in all aspects. It shouldn't be “provide a reasonable alternative to systemd and then we will compare”. “We” won't “compare” anything. Competition is awesome, “we” shouldn't “choose” just one implementation of anything just because the majority of distros uses it. It should be “let people do their thing and please don't hard-depend on this one init system or anything else without a really good reason to do so”.

Just to be clear: I know that among the bigger projects it's just GNOME3 that is planning to hard-depend on systemd and even they want a shim, externnal or internal, to accomodate systemd-less systems (not necessarily BSDs, maybe other linux distros too). Currently systemd is very much optional (opt-out, not opt-in, learn the difference) and I personally mantain an Arch flavour that uses sinit, smdev and a bunch of other small projects while still relying on Arch's package base. It's the attitude of the upstream that seems like a threat: “we want everyone to use systemd”. And if they succeed, developers of userspace software will be very much justified in hard-depending on it. Who cares if everyone uses it, right?