Personally I'm struggling to see the value of keeping the krogan. Despite the turian insistence that the krogan are needed, what does it solve? We don't need headbutting melee fighters. Salarians are a bigger deal than just being able to hold a hammer. Their contribution isn't just that they know how to hold a hammer - its that they invent the hammer.
The reapers cannot be defeated with ground troops. Even if every organic in the galaxy were UberKroganSupreme. What good is ground forces when your enemy is an enormous fleet of sentient war ships? They can blow up the planet if they wanted to. All the ground forces do is make the harvest slower - they are not a solution. The krogan are nothing more than a bandaid that buys you a little more time until the inevitable.
The salarains are Mass Effect's geniuses. Their entire species is kinda designed around to fit in this "brilliant scientists" niche. Their technology is generally the most advanced. What do we need more for the war against the reapers? A bunch of ground meat to throw into a literally endless grinder? Or actual space ships and technology? We spend most of the game fighting ground troops that have been reaperized but remember those are not the actual reapers. The reapers are enormous powerful starships. Ground troops will not win this war, we need fleets to counter their fleets. We need tech, not brawn.
Because it's a game, I suppose that this simply can't happen in the story, but one possible consequence, at least from Shepard's perspective, is that the krogan can potentially pull their support entirely, and the turian primarch decides to simply take his chances and go back to Palaven to fight the reapers, leaving you with no turian assets. The salarians are useful for their technical expertise, but once the Crucible is completed, a powerful fleet that can take the reapers head on might be necessary in order to protect it, and that's something they can't offer.