The Savage cannot compete with anything new released.
The Hunter will have upgrades, more armor, flares, and can even drop bombs.
You can't compare two things that are so starkly different.
Thing is, I could see a lot of people picking the Savage if things went a little differently.
First of all, it has an explosive cannon. Pretty useless to anyone who isn't a professional helicopter pilot, but definitely the strongest weapon in GTA:O.
Second of all, if it were based at all on its real life counterpart, it would be a flying tank. The Hunter gets the luxury of toughness because it's a new vehicle, but give the Savage the same treatment and it's bound to be an improvement over any helicopter.
Third, the missile armament on the Savage is laughable compared to the Hunter, but again this is due to it being an "older" vehicle. The Hunter gets barrage missiles and only has two missile pods.
Now imagine a Savage given the same ability, it has four missile pods.
Finally, and this affects both helicopters, GTA's bullsh*t built-in auto-leveling, that makes using helicopters pointless unless you're looking for vertical take-off and landing (which we now have planes that can do the same thing, so... why bother?)
Remove auto-leveling and make Helicopters handle more freely, and the Savage may just be a preferred choice even without upgrades...
But no, none of the above is going to be addressed so the Hunter will quickly become and remain the best choice.