Depending on the GM you will hear a lot of different things about pitchers and their ratings. Some pitchers with good ratings can be bad for no apparent reason and it drives us bonkers to say the least. Pitchers with so-so ratings also drives us nuts when the team can't hit them for some reason. So I guess it is all relative some of the time. What I like in a pitchers ratings differs from the next person also.
Stamina - Depends on the role I want them for but prefer pitchers with a 60 and above most generally for any role. It is actually hard to get 10 or more on the same roster.
Durability - I like this to be above 25 for most and 60+ for players with a low Stamina.
Control - Depends on the pitcher sometimes, but I seldom look at a pitcher with below 80 unless he has 70 splits and pitch 1 and 2 are very very good. For a closer I like a 90+ control.
Splits - I don't concern myself all that much with these ratings unless I am handing out big bucks. I really like 70+ in vsR and at least 50+ in vsL (vice-versa for a lefty) but will actually drop down to around 45 in both if control and pitches are very good. I like 70+ splits for a closer though.
Velocity - Some like it high as they tend to like strikeout pitchers, I on the other hand like them to be in the off-speed mode. Why? Power hitters like fast balls so why tempt fate especially in the late innings.
GB vs FB - For most this is a personal preference, I usually carry a stingy defense so I tend to try and get mostly GB pitchers. If most balls are on the ground then fewer are going over a wall. Fun fact, Cleveland pitchers give up more Home Runs at home than on the road. Why? Schedule, pure and simple. 81 games at home in a neutral park vs a minimum of 36 to a max of 54 road games in a plus park. The bad part is the offense hits more on the road than at home, go figure.
Pitch1 - I really like this pitch to be 85+ on any pitcher, this is his out pitch btw (from dev chat) so it had better be his good one. There are cases where the splits and control can justify it being in the 70's along with the second pitch.
Pitch2 - I really like this pitch in the 70's or better. I am not real keen on a pitcher that has a better pitch3 either unless pitch 2 is in the mid 60's+ with pitch 3 being in the mid 70's or better.
Pitch3 - I really like this pitch to be 50+
Pitch4 - I like to be as close to 50 as possible or better.
Pitch5 - Is actually a throw away pitch but you better have a good catcher behind the plate if it is below 30. If a pitcher has this pitch, it rarely if ever gets thrown if it is below 30*.
*Although it was mentioned in a dev chat, any pitcher with a real bad last pitch rarely if ever gets used. Though they never mentioned a cut off. What is evident in stats, a pitcher with a last pitch in the low 30's or lower with a catcher whose PC is not in the 80's tend to throw more wild pitches or catchers tend to have more passed balls especially those with a sub-par range or glove. Also wild pitches and passed balls are further enhanced by lack of control below 50.
As for Christian Gordon whom I have checked out. I have one in another World with almost identical ratings, ok mine has better splits but everything else is the same. I use him as a closer, he was 59-61 in that role last season and is 32-33 so far this season. What is the difference, catchers is the only thing I can think of, I run highly defensive catchers with 90 PC in that World. Matter of fact, he is the only setup/closer type I have in that world as I am blessed with 10 pitchers that would be considered #3 starters or worse here.