the shift clicking thing is for those that prefer to use hot-keys instead of clicking buttons.

Be warned, some camps will ridicule you for being a "clicker".
[I couldn't care, as long as you're playing well and having fun]

i raid with 5 full action bars on my mage, and i use probably all but 2 or 3 of those buttons in any given raid.

i COULD use super-complex button setups, but i find it's extremely (as in, i rarely lose time between cast-end and cast-start) fast to combine buttons on the left hand with mouse clicks. polymorph is in the "click" zone, just because if i need it i can usually hover my mouse over it, ready for action. and if i don't, well, i don't want to rearrange my action bars every time i enter karazhan.

"clickers" to me are people who activate ALL of their actions with the mouse alone - that's probably not going to be very fast.

clicking for the initial sheep would indeed be slow as hell, and cause a bunch of wipes. Clicking for a resheep...meh.

wasn't the need for /stopcasting removed in 2.4?

Unless I'm mistaken the /stopcasting here is so that if you need to resheep something you do it right away instead of waiting to finish casting that fireball.

The removing of /stopcasting in 2.3 referred to chain casting where you can now start a cast before your client thinks it's done casting and by the time the server gets the message, you are done reducing latency. Previously the message wouldn't be sent to the server unless you told your client to cancel the spell you were in the middle of casting. Now the message gets send whether you are casting or not as long as you aren't in global cooldown.

I also prefer to remove the /stopcasting for one reason - it also interrupts casting of the Polymorph itself. There is a bunch of mobs that need to be chain-polymorphed (either because of their nasty abilities or because somone is dispelling it) nd it is *highly* useful to be able to spam the polymorph macro to achieve that. If you have /stopcasting in your poly macro and start spamming it faster than 1 click per 1.5s, then you polymorph will never complete making you useless.

that could be simplified to a 1-click macro:

/cast Presence of Mind
/cast Polymorph

(idd no /stopcasting needed here since 2.3)

I personally use the following two macros on my mage:

macro 1:
/focus

macro 2:
#showtooltip Polymorph
/stopcasting
/focus [target=focus, noexists] [target=focus, dead] [target=focus, noharm]
/cast [modifier:alt] Presence of Mind
/cast [target=focus, exists] Polymorph


macro 1 focuses your target
macro 2 focuses your target if you have no focus yet, then sheeps your focus (1-click) or PoM sheeps your focus (hold alt)

The separate focusing macro 1 allows you to set your focus before the pull and get rid of it after the pull (target nothing, then focus target) Spam the second macro to resheep.

Note on the clear -- in this macro you would only use it if switching targets while the first sheep is still alive. (This should be a rare event)