Some ace squadrons have begun to appear with evade defense tokens. They would have been pretty useless apart from long-medium range flak but the new v1.5 changes to the evade token means they are reasonably useful.

Could we see an ace squadron with a salvo token in the future?

It would be the equivalent of counter that could attack squadrons with the normal anti squadron armament and could also attack an enemy ship with the battery armament that uses flak against the ace. It would only take a small rule change to allow a squadron to use salvo with he standard anti ship or anti squadron armaments rather than the rear arc battery.

Its technically possible, but they'd also have to amend the rules so that Squadrons can only Salvo at distance 1 so you can't bomb Munificents at long range, or suddenly be able to Snipe back at Snipe squadrons. I think it'd be pretty niche against ships, and straight-up worse than Counter against squadrons (limited use and vulnerable to accuracies), so I don't think it'd be worth the potential rules headaches and opportunity cost of a Brace or Scatter.

EDIT: On second thought I think it could be strictly better than Counter against squadrons, so it shouldn't be put on anything that either already has or can gain Counter, has a base armament of 4 dice, and/or also has Scatter, because then you've got something that can instantly kill whatever shoots it and potentially shrug off whatever damage it took anyways. It'd be like if a ship Salvo'd with its defending arc rather than its rear arc. So the only thing I can imagine this thematically and mechanically working on is a new Y-Wing ace (either Republic or Rebel), which still sounds pretty niche and I'd rather have the second brace.

I think a much simpler solution to avoid any weird rules or balance kerfuffles would be an Ace that has an effect to spend/discard a token to resolve a Salvo-like effect.

Since squadrons can already have Counter for retaliating against other squadrons, Salvo for a squadron should probably only work against ships, and would probably only be on big single-mini squadrons that are basically ships; like the VT-49.

It would probably only be a single extra bullet to Salvo's rules; but since defense tokens only go on aces and I wouldn't imagine many getting Salvo, if you wanted to do what @Flyinpenguin117 suggests and make it a card effect, then for interaction purposes the effect should probably still "perform" a Salvo attack (just to prevent it from being triggered by or triggering a Salvo). Something like:

• During the Spend Defense Tokens step, if the attacker is a ship at distance 1, you may perform a S ALVO attack using your battery armament instead of resolving that token's effect.

As a card effect it could also be fine-tuned, in case it would be better to have a specific number or color of dice instead of whatever that squadron's battery armament is (for example, if it's a Bomber with black battery armament but you want it to have red pseudo-Salvo). And it could introduce some interesting choices if the ace only has one defense token or one type of token (can't spend 2 brace, as opposed to if it had brace+salvo).

I think counter kind of covers it.

From a game perspective I don't really care as long as it improves the game.

About the mechanic it definitely comes with some minor reworks on salvo to make it work.

From a flavor point of view I don't see a squadron taking heavy fire from a ship and recklessly answering the fire instead of running away to try another run later when the guns are firing something else. But it might be well cause with salvo and I imagine something like "don't care, we will stand against the fire so return fire!" Which is basically what salvo token does: you take all the damage cause you hope it won't be enough. I like to think that a squadron has 0 chance of doing something like that again ship. Instead, they survives cause they are nimble and can easily run away from shots instead of going straight through enemy fire. I always read the low damage from ship against squadron comes from squadrons being evasive even when they don't actually moved in the game. Just like engagement rules also show.