Star Trek

TNG has aged well and despite some dated elements it is still within the comfort zone of modern audiences. TNG created the baseline for how following Trek shows for decades would look and operate which gives it a connection to all of those shows for people to grab onto. TOS is both older and of a significantly different wavelength. I personally love it, but a lot of people bounce off of it. That is why there is more openness to rebooting it. Also, the JJ Abrams movies have broken the seal, as it were, on the idea of recasting TOS characters, making it less of a major step. This is why people at large talk about it.

SNW also slowly and softly incorporated the building blocks for a TOS reboot spread out of time, rather than just dumping the idea out all at once. This assembly was made more palatable by fitting the process inside of a pretty good Trek show.

In terms of canon, it is much easier to introduce a TOS reboot than a TNG reboot. A lot of things in TOS have had to be explained away in convoluted ways or mostly ignored by the rest of the franchise. TOS is more ripe to be retuned with details that fit better into what Trek has become. TNG has a much tighter connection to the rest of the shows.

For what it's worth, I don't think either TOS or TNG should be remade. A new Trek show should always expand or move Trek forward in some way. I am tired of reboots, reimaginings, and rehashes.