system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] What potential reasoning could the new stormtroopers have for their new costume design?

Like is there anything tactical or logical about it or is it just to make it look sleeker? I mean I can only assume they just threw out the old ones.
gpt
As with all military technology, eventually flaws are discovered. The empire would have received feedback from the troopers, suggestions from them regarding how they think the suits could be improved, what elements they lack. 

For example, If reports keep coming in of troopers taking a hit in the arm, and the internal electronics keep flickering out because of that, then Imperial R&D know that they should stop locating the internal power source in the forearm sections of the suit. So in the next version of the armour, the same power source might be located in the helmet, meaning that they need to move some other things around to accommodate that. This might mean that the helmet now looks different from the outside. 

Also, general technological improvements. If a new target scanner is developed on Corellia and is being used on their mall security droids, Imperial Intelligence will get word of this, once they've been to Corellia and confiscated all of their mall security droids they can pass them over to Imperial R&D who will back engineer and include that new tech in the next version of the armour. 

Eventually this will result in armour that looks different, rarely will any military spend that amount of money to upgrade armour solely for aesthetic effect.