One thing that always annoyed about vanilla was the very limited defense options in the gun/laser/flame turrets and a basic wall. Artillery turrets are specialized. Be nice if vanilla had a rocket/cannon turret of some kind to expand that much, at least, as such ammo is already there and has no automated combat use.

Some mods have added turrets, others better walls, and some new options like barbed wire-style concepts, or a mixture of them.

What about something like a plasma fence that severely inhibits movement, causes damage to passing entities, and draws power? Or something based on this, like a similar sort of thing you put in front of your walls, so turrets are not the only damage dealers?

What about some sort of chainsaw or other short/melee range defensive emplacement to guard the other turrets? Shotgun slugs could be a potential modification, like the tank flamethrower behaves differently from the flamethrower/flame turret.

I recall Reika implemented energy shields that protect a radius for a lot of power, and there are a lot of weapon concepts to draw from across the gaming world and the real world.

One of the great things of Factorio is clear use of items, but conversely one of the limits is this helps highlight use case holes that nothing fills quite right. You can figure out solutions, but see limits you cannot get around.