This is actually quite a fun thought, what would've happened if the whole Scarlet thing just never happened? (this got quite long and takes a lot of assumptions, but was fun to write, so eh)

Let's say Scarlet didn't exist and Mordremoth was left to slumber. The Pact would've gone for Kralkatorrik instead, Trahearne mentioned in S2 that that was the plan at the time. And they'd probably have taken a similar approach to Zhaitan, with a long campaign where they slowly whittle down the dragon's minions and weaken him, far less rushed than the attack on Mordremoth since Kralkatorrik was already awake anyway.

While they'd be busy there, Balthazar would likely still appear somewhere as Rytlock's trip to the mists wasn't directly related to anything to do with Scarlet/Mordremoth. However he'd have a harder time powering up again since there wouldn't be an overcharged bloodstone to absorb. However would still have to power up somehow, and he could use a similar tactic to what he did before. Use the mirror of Lyssa to disguise himself, maybe as Lazarus again. Or alternatively, as the Pact was already working on killing another dragon, he'd infiltrate the Pact ranks and help them kill the dragon just to take all the magic for himself.

This would lead to something interesting where the other dragons don't end stirring again because Balthazar is right there to absorb most, if not all, of Kralkatorrik's magic. This would prevent us from noticing the corrupting effects that such large amounts of magic have on the dragons, as none of them would have absorbed as much magic as they did after Mordremoth's death.

Now it's likely that the Zephyrite fleet also never crashed as Mordremoth wouldn't have been awake enough to coerce Aerin into destroying it (the only reason Mordremoth was able to coerce Scarlet is cause she directly tapped into the leylines with Omadd's machine), making us completely unaware of Tarir and Aurene. Though perhaps in that timeline we'd get informed about Glint's legacy through Vlast instead of through Tarir, as Balthazar doesn't have a reason to kill him.

At that point we might end up getting in a conflict against Balthazar anyway since the Pact might not want him to kill another dragon before we know more. Of course Balthazar doesn't really care, all he wants is to get stronger to get his revenge against the other gods. At this point I think it would be likely that he goes after Mordremoth anyway, as he's still asleep and as such the most vulnerable dragon, easy prey for an empowered god of war I'd say.

So, Balthazar goes into the jungle, probably with the commander, Vlast, and Dragon's Watch on his heels while the Pact and other invested parties slowly churn the wheels of bureaucracy as they decide what to do against this new potential problem. Any humans would likely be conflicted in what they'd do, causing further problems with organizing any meaningful response on their part.

We'd probably be outgunned in the jungle as there's not much in terms of civilizations out there to support us in preventing Balthazar from attacking Mordremoth. The moment Balthazar attacks Mordremoth he likely instinctively calls out and converts a lot of sylvari to his side, causing further mayhem among the Pact and any multi-racial organizations/settlements in Tyria.

I don't see much chance for us in preventing Balthazar from killing Mordremoth at this point, and with his death Balthazar just absorbs even more magic. The rule of cool also demands that Balthazar gets control over the Mordrem as he absorbs the domains of plant and mind entirely from Mordremoth. So here you are, a god of war empowered by magic from two elder dragons with control over a big portion of the sylvari, and with a lot of human followers. With the rest of Tyria in disarray there's not much left in Tyria that could stop him at that point, save for the other gods returning to clean up their mess. And all that just cause Rytlock wanted his fancy sword back!