All it took was a couple easy modifications to turn this completed design into the perfect sniper rifle.

How do you know they didn't? This was near the end of DS9 and we didn't see much on the ground fighting from the war to know if they employed it. Voyager was stranded in another quadrant so wouldn't be privy to Fed's latest tech. ENT was a prequel.

There was simply no chance to see whether they adopted it (nutrek isn't real so I'll ignore any comments pertaining to that)

>>212322750 (OP)
Video game called Star Trek Elite Force. Quite good actually.

Starfleet like wearing pajamas and using stun pistols. Just like Klingons like using swords. Once you reach a certain level of tech you have to pick and choose what you actually want to use to enjoy life. Not what is most sterile and effective.