To answer your why should it be changed , then this would make the "tower defence" part of playing factorio more interesting. You would need to make a balanced compromise between AOE damage (flame turrets, mines), DPS (poison), high-dmg-low-rate-of-fire (lasers) and general-purpose (gun turret ...

I was thinking of putting the idea of electric boilers in a brand new thread, but after searching then I decided to bump this thread instead. In short I would like to see electric boilers introduced to heat water during daylight hours using solar panels, and then redirecting the hot water to ...

TLDR ; Implement terrain and/or situations which restrict familiar designs or combat strategies.

Why
To avoid players getting stuck re-using the exact same blueprints for factories, or re-using their "perfect" combat strategy all the time, try and force situations where they have to think ...