Yes. YES. YESSSSSSS!
THIS is how an endbringer kill should be reacted to! So many stories have it being either a "great, now what" or an intensely private celebration thing, but this perfectly shows how I believe people would react to this.
Also, if that WAS a replicator... well, the Alterans have tech that the Replicators can't beat as is, and there's no way to adapt to something if you get annihilated on a subatomic level before you can give any scans of it to your leaders. Alterans vs Reps in SG universe would likely be the reps victory, but that's just because the Alterans had practically no military culture.
If they'd been tactical and/or more aggressive even the Wraith would have definitely lost, considering the sheer
capabilities of the Alterans.
In addition, I'm curious: is this actually in the SG universe? Shipyard said the stargate worked, so doesn't that mean there have to be stargates elsewhere? And if so, just what is the discovery of a 2nd earth and someone who can summon Atlantis-sized cityships complete with armaments going to do to it? I presume the Ancients are going to flip their shit at a living, non-ascended lantean, but... well... he has all the blueprints created by the Lantean civilization. That technically should include Moros's shit and the Dakara superweapon.
TCGM can we get a WOG on this?