Completely disagree. Of course there is 'tactics' and 'skill' needed without friendly fire. The enemy isn't easier to kill just because you can't frag your teammates, is he? You need to think just as much about what you are doing if you want to win over your enemy. Only difference is you can focus all your attention on him, resulting in a deeper combat experience with the enemy
It's not easier to kill your enemy with FF off.
it is, for instance if you see an enemy and a teammate close, the teammate has not seen the enemy, but you have, and you have a rocket launcher and a rifle, what do you do? in FF off servers, you just blast the rocket, kill the emy without aiming (easy), teammate continius looking in another direction without a clue of what just hapened. In FF on servers, if you are an idiot, you still blast the rocket, kill both guys, recieve penalty for not thinking. OR, draw your rifle, aim quickly ans steady (hard), fire, save your team mate. The last example, also raise inmersion, because now you are into a task (a small one), save your teammate, kill the enemy before he kills him.
There are mutiple cases where having FF off makes playing a lot easier, enemys and frienlys in a building? smap granades, farm points. enemy tanks near buildings with friendlys? Arty the hel out of him, watch firendlys come out of the dust, unharm.