I'm a great advocate of alts (as you can probably tell from my choice of blog). The main reason for me shouting this from the rooftops though is that I don't think you really understand how all the different bits of WoW work unless you experience them for yourself.
As the saying would have it, "Before you criticise someone, walk a mile in their shoes. That way when you criticise them, you'll be a mile away and have their shoes!" ;)
I just don't think someone can understand the processes involved in playing a tank/healer/dps/whatever unless they have actually tried to do it themselves. It's not the only reason I play a lot of different characters (but I'll get to the other reasons at another point), but it is one of the most important in my mind.
When tanking, I've had dps shout at me saying "Generate more threat!". That's despite them being in purples and me in a mixture of greens/blues and me having no rage.
I've had tanks moan about dying when I'm healing, despite having run ahead of the group to pull when I have zero mana and am drinking at the time. Then again, I've also died in a fight after a ready check having received no heals whatsoever in the ten odd seconds it took the mob to kill me.
And, I've had healers moan about pulling aggro when the fight is half a minute old and the single mob we're fighting has no sunders on it whatsoever.
If you know how the other classes operate, a lot of these issues seem to go away. Other members of our guild who've played a tank have realise there is an awful lot of button mashing that goes on to be able to survive some of the encounters and generate enough threat so as not to severely hamstring the dps via threat caps
Those who've played dps know that balancing their crowd control duties whilst putting out decent damage can be tricky. As can threat management whilst killing the bad guys in a timely manner.
Those who've played healers realise it's tough to keep the tank up when everyone else in the world is pulling aggro and/or getting hit by the mobs cleave or AoE.
So, I advocate trying at least one of each of the holy trinity (tank/heal/dps) to get a feel for the stresses and strains of all the different facets of the game. At least that way you'll appreciate how good some of the others in your guild are at playing their classes. And how bad... ;)
Roll an alt today! It may make you better at playing your main.
