As an RPG/FPS hybrid Mass Effect is fraught with conflicts in active and passive management. What should be a process in a menu screen and what should be running process on the battlefield?
ME does allow active ammo load management on the field, via skills.
ME1 used mods for that - and you could swap them in the field, too.
There is a middle ground with ammunition that encourages (but does not require) varied play while not fully restricting freedom.
I don't want to be "encouraged" to play any particular way, at least not when the method involves "punishing" me for trying to play in a way that best satisfies my preferences.
Add in the option of ammo scarcity at higher difficulties and the weapon variety of Dead Space 2, and I think the result would be fantastic.
Unless you adjusted quantities by vocation, ammo scarcity would punish some vocations more than others. You'd also need to be more meticulous in balancing weapon designs, and ostensibly more forthcoming about weapon stats.
I'm open to ideas as long as they push the ideal,
The ideal being... ?
since you get to decide what goes in your inventory, you can allocate as much room to each kind of ammunition as you please (until your inventory caps out of course).
In FO3, ammo is weightless. You can carry all that you possess.
But here's the thing: Mass Effect is a shooter.
So I've been told. It was initially marketed as an action RPG.
Fallout is also an RPG that happens to use shooting mechanics.
I reference Wolfenstien because it, like Mass Effect, follow the old shooter convention of letting the player have access to more than two weapons at a time and as such, provides a good outline (though loose it may be) on how to keep shooter combat consistently engaging with its ammunition system.
I think level, encounter, and enemy AI design have far greater potential to keep combat (whether you choose to shoot or not) consistently engaging.
But why though? Is it merely because you didn't like ME2's implementation or do you genuinely think there's no way Mass Effect could do better?
From the inception of the IP, ME weapons have had a very different technological basis than any other firearms. Adding ammo now would be a sea change in the technology, and change the flavor of the series.
Also - I genuinely think the overheating mechanic is as good as it gets. It restricts how much you can shoot over time, which I find preferable to a cap on how much you can shoot, period.
In my mind, ammunition would only be a resource for the player. As I said: it's another vector of difficulty in active strategy that requires players to be precise, use all the abilities at their disposal, and consider context to enhance the potency of their actions. It works well in other shooters and it can work well here.
It doesn't serve as a vector of difficulty when all you need to do is camp in cover and wait for your squadmates to finish the battle. It just means players are camping in cover instead of playing. In order for some limitation to be meaningful, it needs to be applied to all allied combatants.
But it isn't. Ammo management encourages power usage. Just look at Shadow Warrior 2013: scarcity with weapon ammunition encouraged the use of the sword and its various abilities. You could play the whole game with just the sword, but you didn't have to.
The overheating mechanic also encourages power use.
People who already make heavy use of powers would not be impacted.
People who like to shoot a lot would be unhappy, though some of them are also unhappy with the overheating mechanic. A mod that would install a permanent heat sink might satisfy some of them.