I think that all of this goes to show how very, very long it has been since the Federation has been involved in a serious war of any kind.
In TOS, the Federation was fresh out of the Romulan War. There were people who remembered it and their equipment tended to reflect that (within the restraints of Mr. Roddenberry's utopian vision, of course). The 'Enterprise' had decentralised weapons controls, for instance, were each phaser battery had its' own control room that could (theoretically) continue to operate even if the bridge were disabled ('Balance of Terror' - my favorite episode of all time). Security units, despite their ridiculously visible uniforms, seemed fairly competent and could hold their own hand-to-hand against a group of Klingon borders ('Day of the Dove').
By the TNG episode, the entire Roddenberry uber-socialist utopia bit had completely corrupted the design and feel of the series to the point where there were no guards even on the most sensitive ship facilities (main engineering and the bridge). The Federation hadn't faced a serious millitary threat since the collapse of the Klingon Empire. After all, the 'Cardassian War' ended during Season 2 of TNG. The fact that it never affected the mission of the Federation Flagship suggests that it was just a prolonged series of minor border skirmishes. Only the Federation would secede a huge area of space for peace after such a minor conflict.
This long period of peace resulted in totally impractical handweapon designs, including the laughably unusable 'handivac' Phaser II pistol, which was rapidly re-modelled because even the actors couldn't use it, until it reached its' current pseudo-pistol form. However, the concept of a firing button on the most exposed surface of the body rather than in a protected spot (say, the traditional 'trigger' spot) remains an oddity unique to Trek. Roddenberry said that he wanted to make the weapons look like that people were consciously moving away from the projectile weapons designs of the Bad 'Ol Days. Why? The designs
work and are the result of something like 200 - 300 years of engineering and ergonomics research? Why fix what ain't broken?
The Phaser III Carbine (my name for the original rifle) is an example of this ridiculous trend. Over-engineered, impractical to use (requiring an impossible sub-machinegun-on-the-shoulder-without-stock firing position) and with components that look like they will just snap off. On the other hand, Romulan and other-power designs look like contemporary weapons and are probably much more reliable. That Klingon carbine that Kira used in one DS9 episode is an excellent example.
After so long considering themselves the top of the Galactic food chain, above and immune to the trials of lesser species, the advent of the Borg, the Dominion War and first contact with the New Galactic Empire must have come as a dreadful shock to the utopian Federation...
