No, balance is very important.
It is true that sometimes by making stuff more balanced you can make the game less fun (No Items. Fox Only. Final Destination), and I would bet a lot of money on the fact that if you removed the super-powerful items like the Blue Shell or Bullet Bill from Mario Kart it would be significantly less popular. However, that's a particularly slap-dash approach to balancing - it works for the competitive scene (like how in Left 4 Dead 2 competitive lots of things are removed - Med Packs, Defibs, Grenade Launcher etc.) but real balancing isn't about removing features, it's about tweaking them. You can have a balanced game and a fun game.
Point is, if you don't balance the weapons the game becomes stale and repetitive. When there's no reason to use anything other than one particular gun, it removes variety from the game; in Black Ops, there are 32 different primary weapons, and of those 32, maybe 8 or 9 are used regularly. Think how much better the Call of Duty series would be if all the weapons, killstreaks and perks were equally useful, you'd have an endless amount of combinations to try out and be able to do equally well.
I'll give an example of how weapon balance can really make a difference. In Left 4 Dead, the Autoshotgun was easily the best Tier 2 weapon. There was no reason to pick the M16 or Hunting Rifle over it, so every time you played Versus everyone just picked the Autoshotgun and it became very stale. Fast forward to Left 4 Dead 2 where Valve did some significant weapon tuning, now all the Tier 2 guns are very well balanced - the Hunting Rifle was now useful, and the Autoshotgun was nerfed to the point in no longer dominated. Now if I play Versus I can pick whichever gun I feel like using, because I know that each of them are just as viable, and have their own strengths and weaknesses.
And the last thing is that whilst it's fun to dominate other people with cheap tactics, it's frustrating for the people on the receiving end. You can't just take into account one group of players, you've got to take into account people on both sides of the situation. I might have fun gunning down 20 people in my Chopper Gunner, but I've been equally frustrated when I've died over and over and over to a killstreak I didn't give away.
Tl;dr - Less balanced =/= more fun. Yes, you can make a game more balanced and less fun at the same time, but they're not mutally exclusive. Unbalanced games remove variety and add frustration, and you don't want that.