Ruin is horrible and anyone would welcome them on the opposite faction, unless they're horrible too.
The problem is in world PvP you can be 100% awful so long as you got the numbers it doesn't matter these days. There has been a game in years where 2:1 odds on a large scale (IE: 100 people vs 200 people) can be won simply due to game mechanics. Even if the 200 just did auto attack it's more than enough to take down the 100.
That's why in WAR Ruin basically ground Dark Crag into the dirt. Not because of skill, honestly they were terrible, but you don't really need individual skill if you can herd the zerg into the right direction to trample your opponents. Once the Praag merger fell into place Ruin was getting routed regularly because there was actual competition at that point.
It's also why population ratios actually mean something. With Huttball you can easily que up against your own faction so there's always Warfronts to do so all that will ultimately end up mattering is World PvP where numbers mean everything.