Sorry for the long post, I just wanted to make the meaning(what they mean to me) of all the terms i use clear so there is no confusion about what im trying to say.
This is a general observation about gunships,bombers and balance in FA.
First thing, some terms i wanna define and use:
1)The cost effectiveness of units - how good a unit's stats are for its mass energy and build time costs.
2)the role of a unit - when is a specific unit the best unit to build under given circumstances.
Those circumstances define the unit's role in the overall balance.
If a unit is never the best unit to build, under any circumstances, than it is under powered and useless.
there is no point in a unit that always does what needs to be done worse than some other unit.
These two terms are sometimes interchangeable and are connected.
Let's say in a cybran T1 land factory we have two units, Mantis and Mantis 2.
They both have the same exact stats, operate in the same exact way and cost the same amount of all three resources(mass,energy and build time).
These two units fill the exact same role of a t1 main tank, because of how they handle, their range of fire etc... and do it at the same cost efficiency since they cost the same.
Now I wanna get to gunships and bombers.
Both are flying units, both are mainly ground attack units so what makes them different? under what circumstances is a gunship better than a bomber and under what circumstances is a bomber a better use of resources than a gunship?
Except the usual stats about dps, damage per hit, speed, health points, there is major difference between the two units.
They behave and move in two completely different ways.
Gunships hover over the target and bombers fly in big arches around the target.
What is this relevant to? How do these two different behaviors change the roles of both units and separate them?
Both units are countered by AA units, like fighters or AA structures.
So when is a bomber the ideal weapon of choice? when you want to surprise your enemy that either has not enough fighters or they are located in the wrong place or your opponents simply does not have any fighters.
The advantage of the bombers is that they come fast, deal a lot of immediate damage for their cost and can even be sent on suicide missions since if they just unload their bombs once they are already worth it even if they die afterwards to AA.
So is the gunships the same? No, the gunship does not deal a lot of immediate damage for it's cost so it is ideal when the enemy has very little AA or none at all, allowing the gunships to deal accurate damage for an extended period of time.
the question than is, when the enemy has no AA why not just use bombers in this case as well?
Because there are two different types of AA.
1)Mobile ground AA and mobile air AA.
2)Static AA, turrets.
Does this have any effect on the roles of bombers and gunships?
I think it does.
As mentioned before gunships hover above their target while bombers are much less conservative about the space they use when attacking and fly in large archs.
What does this mean? It means that if a player has been spamming STATIC ground AA if a bombers comes in with his big flying archs it has a big chance of getting inside the radius of static AA and getting hit.
Gunships on the other hand can attack areas with static AA in the vicinity without fear of flying into their radius because of the fact gunships do not use up much space when attacking.
When the enemy has fighters that can move around and get to the gunships no matter where they are, bombers have the advantage because they only need to do one successful surprise run and it does not matter if they are killed afterwards.
The problem in the roles of a gunships versus the bomber arises if an RTS has no viable spammable static AA for cost.
As in, the static AA, for its cost, is usually worse than just using fighters.
This means the main attribute of gunships over bombers becomes irrelevant since nobody is spamming static AA in his territory.
gunships loose their place in the balance and their roles starts blurring with the role of bombers.
The point is that if spamming STATIC AA is almost never viable, and mobile AA is almost always the better choice, gunships loose their role and then devs must balance them to fit into roughly the same role of bombers.