(cough cough, clearing throat, climbing up on soap box)
I fully endorse starting turns with movement of the front foot. I also advise my students that they "go where they look". To the extent that Danny's advise leads to that this is good. Dropping the shoulder could lead to shifting to toe side on the front foot. Raising the shoulder could lead to shifting to heel side on the front foot. Both moves could be used as cues to initiate lower body rotational movements (e.g. knee rotation).
I'm not a big fan of starting turns via shoulder movement. I tell my students we turn with our feet not with our shoulders. I prefer to see the shoulders lined up with either the board or the stance angles. To the extent that Danny's advice develops a habit of turning the shoulders as a the primary means for starting a turn, one could easily end up exactly as described.
On groomed snow, I'm constantly trying to get my students to move weight forward to achieve a centered stance (note that I often demonstrate an exaggerated forward stance to achieve this). Movements of the front foot are less effective when there is less weight on them. In powder (to the extent that it is deep), we shift weight back (relative to groomed snow riding) to keep the nose of the board up and use our back foot more as a rudder. Trying to steer only with the front foot in powder is (ahem) difficult.
There are two basic approaches to controlling speed: skidding and using turn shape. Throwing your board around is skidding. It's effective but it is not very efficient. Inefficient movements tend to become ineffective when the level of difficulty is raised (e.g. steepness, powder depth). If you can let your board turn you (vs you throwing your board around), you can control speed by controlling where your turn ends (finishing going uphill if need be)..
When I teach riding, I teach my students 4 ways one can make a snowboard turn. Here's the simple version:
-Pressure - whichever foot has the most weight is the one that wants to be going downhill more
-Rotary - you can rotate or scissor your feet and the direction a flat board is pointed will change
-Edging - putting the board on toe or heel edge will cause the board to start turning as it follows the shape of the sidecut
-Twist - starting edging movements with the front foot first will cause the board to start turning (this movement twists the board)
Those 4 elements can be caused by either bending/unbending body movements or turning body movements. When you have learned which body movements are required to achieve a specific element, you are on the road to becoming a successful rider. For example, to get off a lift without falling you can put the board flat on the snow, stand up, straighten the back leg and bend the front leg. This will load all your weight onto the front foot and enable you to ride straight down the off ramp. Another example is using an arched back to aide toe side edging. When you can blend any amount of all 4 elements into a single turn, you will have all you need to ride anywhere on the mountain under any conditions, with one small exception (dynamic turns - as noted above). In my experience, if you learn to ride this way then you will fall a lot less.