Ugh…
Just went into practice mode to try it. It’s no wonder I’ve been so confused. I’ve always said it is an ender, and it is - it’s even listed in the command list. It’s the fact that the devs said it wasn’t when referring to my setup that got me all confused - the way they explained it was just terrible (no offense, devs!) because, at least to me, it seemed like they were talking about ruin in general, not just in that specific circumstance. I’ll go back and re-read it though, just to see if it’s just me (it probably is).
That being said, for an ender (sans wall), ruin is really, really bad. It does crud for damage, isn’t a heavy knockdown, and has no real redeeming special qualities at all (such as being a battery ender, etc.). Sure, it gets you some spacing, but the recovery of the move and the ability your opponent has to quick-rise makes that almost negligible, not to mention the fact that it’s just far enough away to not really be at a useful range. It also hits the wall (the regular stage walls, not Aganos’ cyclopean walls), but it doesn’t cause an actual wall bounce, so it’s not a wall bounce ender (which, at least with the regular stage walls, I think it should be).