Ah! Now I know the true reason I haven't reached higher on the ladder: I save every replay ... and rename them all! Obviously, any time I might have spent actually gaming is tied up in such a meticulous activity.
I also saved all my reps back in BW. Who knows how good I might have been if I hadn't. And yes, I even manually saved reps when I used penguinplug's autoreplay function.
Incidentally, I dled the program and did a quick check of my games.
TvZ: 42%
TvP: 33%
TvT: 81%
ZvT: 37%
ZvP: 71%
ZvZ: 66%
PvT: 64%
PvZ: 75%
PvP: 72%
I'm amazed my PvP ratio is that high. Like, seriously surprised, but the other numbers don't surprise me. Similarly unsurprising: I have an 83% win rate in games where I'm teamed with FighT. Mass sentries, baby, they're (almost) unbeatable.