Like Lev stated, the sticky is much more than the rail gun. The rail gun tends get indirect hits causing less than full damage inflicted on mobile targets. Like High stated, lasers and micros have a faster firing rate and are cheaper. Hell, in some games, I've been known to use tiger mics over rpgs because they fire so fast it makes my M240B jealous.
Eden can make things interesting on long 6 player games. Usually one side remains mobile and loose while the other digs in under an umbrella of meter defense.
Being in the sandbox, I can't exactly play OP. It seems to me that the problem is that those who do play, would rather change the rules of the game, rather than make the rules work for you. Examples are getting vehicles in the mountains, destroying your opponent without "touching" them (
http://wonbirdsofprey.tripod.com/puzzles.htm, puzzle #5), building 2 advanced labs off the start (yes, I had a research order that took advantage of it), emp'ing your own vehicles (I hope some of you remember that one). All of these were thought up by someone. They didn't change the code in the game to make it happen, they just took advantage of how the game is played. Remember: "It's not the weapon, it's the brain behind the weapon that's dangerous."