When you are expected to switch between weapon sets to maximize the potential of your class, it just seems clunky. What I want, or any player should want is to have fun. When you involve macros beyond focus targets and delve into equipment switching, combat stops being fluid.
That said, there should be an ability to effectively switch between sword/shield and your offensive weapons (whatever they may be). Now that talent specializations are picked, an ability can reflect your specialization (If you're Arms, you switch between your strongest 1h/Shield and your strongest 2h weapon. Fury based on your last tier talent would choose between your strongest 1h/shield and whichever talent you chose.)
Battle Ready
Instant
10 Rage
The warrior switches between his defensive and offensive weapons, equipping your strongest shield and weapon or weapons, depending on your talents and what you currently have equipped. If you switch to a Shield, you automatically reflect the next spell cast at you within 3 seconds. If you switch to a two-handed weapon or dual-wield weapons, your next Mortal Strike, Bloodthirst or Devastate become a critical strike and can be used with any weapon type. These effects can only occur once per minute.
The 3 second reflect isn't there to actually reflect, it's to give the warrior some breathing room. If a skilled player is smart enough to notice the switch, then they can just wait 3 seconds without coming to harm, and prepare themselves for spell reflect. The warrior can now involve more strategy by having Spell Reflect (the ability) to use at another time.
The rage cost is there because you avoid the GCD and gain a benefit when immediately switching. To avoid spamming, the effect can only happen once per minute.
There can also be a talent in prot that allow them to use this skill, if they choose to do so.
Defender's Devastation
Whenever switching to a 2-Handed Weapon with Sword and Board, your armor is unaffected and you may use abilities as if you had a One-Handed Weapon and Shield equipped. Lasts 5/10 seconds. Can only occur once per minute.
Just imagine Shield Slam ---> Slamming with your 2H. Shield Bash ---> Bashing with your 2H. Blocking ---> 2H. Shield Block ---> Using your 2H to mitigate damage (You are a skilled defender, anything and everything is your shield).