Cause when you have 4 weapon slots, an Elemental Autogun would be preeetty handy.
And it would be a nice thing to have, because the Autogun is kind of unique due to it's specialities and i think there should be Shadow and Elemental paths of them, too.
Name ideas:
Elemental Autogun 3*: Leaf Wonder, Nature's Rampage, Tesla Array
Elemental Autogun 4*: Bud Wonder, Wild Rampage, Power Array
Elemental Autogun 5*: Treerific Wonder, Discharge Array
Shadow Autogun 3*: Lurking Surprise, Unfateful Faith
Shadow Autogun 4*: Super Surprise, Untrusted Faith
Shadow Autogun 5*: Dark Surprise.
Yeah I'm a bad namer.
No weapon series in the game caters to all damage types (except antigua series, which still doesn't cater to all 3 possible damage type pairings)
This is likely to force players to have some weapon variety. All piercing swords play differently from any other sword type, the only pure shadow/elemental swords are slow 2handers, various status effects can only be caused by specific weapons. There aren't any piercing bombs that have a blast radius, they all shoot projectiles everywhere.
Some weapon types are too good to be available for every damage type; give me a piercing pulsar and a shadow pulsar and I literally wouldn't use anything else, except maybe a piercing sword for wolvers. Autogun may not fit in that category, but it's still important to realise that variety has to be enforced in weapons. I agree with what appears to be OOO's current design paradigm, that no weapon line should have more than two damage types at a given * level.
The fact that there's a normal damage autogun further reduces the need for elemental or shadow variants, as you could just use normal for everything if you want it to be useable against everything.