Well, neither lightsabres, nor miniguns are used as the infantry weapons. With current state of affairs, with no cybernetic implants or mechanized battlesuits, it`s not realistic for PHALANX soldiers to use such a heavy weapon as minigun. Besides, how would it differ from machine gun?
Because the use of man portable particle cannons with knockback capable of blowing people off their feet without cybernetic implants or mechanized battlesuits is realistic, or plasma blasters so large, heavy and cumbersome that they can only be practically hefted by Ortnoks and UGVs. Further, an advanced design, minaturized infantry level minigun is nowhere near in the same category or league as a lightsabre in terms of implausibility. Some sixty plus years in the future, where humanity is capable of attaining technological singularity, is such a comparitively modest innovation beyond our means to create? The dubiousness of this is compounded by the fact that military technology has historically been, and presently is at the forefront of technological innovation and implimentation.
The minigun at present also differs from the machine gun in a variety of important ways, gameplay wise. It features greater efficiency (damage/tu), greater fire rates, a larger clip size, two handed operation and holding and less accuracy. In short, it is the king of suppression, and is one of the best weapons for close/medium range encounters versus medium and lighter armour. While it could, like most other firearms, use some tweaking, at present it is sufficiently unique to warrant inclusion in the human arsenal.
Anyway, base human weapons already offer a great variety, it`s other game areas, that need serous improvement. Visibility system (currently soldier can see through entire map LoS provided, there is no way to sneak), being able to set something on fire, improved air interceptions and so on...
Actually the human arsenal could use a great deal of work, with respect to both balance and gameplay. There are several unfilled niches that should be addressed and accounted for, and several weapons that are either over or underpowered, and/or have completely unsensible properties.
Are you just guessing, or have you developed freeware games, and/or asked developers this question?
I don't speak for the devs here, but as a developer on other projects and a contributor to this, my main motivation is that the process is fun. Certainly working on something that will be shared with other players adds to the fun. But if the players (as very unscientifically represented by a few vocal forum users) don't like something which i'm convinced is a way to go, my motivation is not effected. It's simply not possible to make everyone happy, so it's not my goal.
I see no problem weighing the wishes of developers over those of the players. Projects die much more readily from loss of developers than loss of players.
I am not guessing. I have done development work for various teams in the past, and have done solitary work (custom maps in warcraft 3, and modules in NWN for example). Personally I have mixed feelings about the actual process, with the main incentives for the work being both my personal enjoyment of the finished product, and the recognition and enjoyment of others who will play it with me. The majority opinion thus, in so far as I have been able to gauge it has been the predominant influence on my work. These sentiments have often been shared by those I have worked with, so I am not making speculations. Of course, there has been the occasional developer who wanted to skew things selfishly for his own personal satisfaction or enjoyment at the expense of the playerbase, and rightfully, his actions were either overturned or he was outright dismissed.
Further, even though you are correct in your assertion that the majority is unscientifically represented by the opinions of forum posters, it should be noted that these posters represent a sample that can usually be extrapolated to gauge the general sentiment of the playerbase at large with reasonable accuracy.