One size doesn't fit all.
What's sauce for the goose is not necessarily sauce for the gander.
Speaking from my own experience---I pitched for seventeen years, many moons ago, and I can only say that there is no one way to pitch to a batter. You have to know a batter's strengths as well as his weaknesses, and you have to know your own stuff, what you're capable of doing. Let's look at the second statement first.
"Show your off-speed stuff and your changeups at the beginning"? What if you're a snake-jazz pitcher who throws only breaking stuff, if you don't have anything resembling a fast ball? That's what I was, a finesse pitcher whose top speed was 81 miles an hour, so I wasn't fast by any stretch of the imagination, and I had to rely on breaking pitches AND very good control and command of all of them. My two best pitches were a sharp, late-breaking slider which I nicknamed "Filthy McNasty" (after a character in a W.C. Fields movie) because that was exactly what it was,
and a very good knuckle-curve, and I built my whole repertoire around those two pitches. I had learned to mix up my stuff---my pitching coach, an active major-leaguer in the Yankees' rotation in the early 1950s, told me: "Move the ball around---high, low, inside, outside, and change speeds. And you know how to do that." I did, and I used a lot of my other pitches to set the batters up for Mr. McNasty, and I got a lot of strikeouts that way.
As for the first such comment---there are many things you need to consider as far as the batter goes, not the least of which is where he's standing at the plate, and whether he shifts his position, whether he pulls away from the plate as he swings (you can go after them with a good outside pitch), whether he uppercuts or chops down at the pitch, whether he crowds the plate looking for something he can hit to the opposite field.
These and other things will tell you what his weakness is, what he can't hit, and you can't go wrong going after him with such a pitch. For instance: word got around the National League that Stan Musial did not like sliders, and so the pitchers fed him nothing but, and he hit them on his fists and popped them up. Two things to remember: don't throw that batter anything down the pipe, because you can be sure he'll be looking for it (unless you really throw that cheese), and don't ever give him the same pitch in the same place at the same speed, because if he misses the first time he won't miss the second time. And---here's something Babe Ruth once said: A good changeup will cause batters more grief than anything else, so if you have a good changeup don't hesitate to use it.
Strategic pitching. That's what it all comes down to. 8) :baseballpitcher: