Bucs Dugout is now probably widely read enough, and the conversations here are detailed enough, that it might be helpful to make a list of some principles that underpin the arguments I make. I'll probably write these pieces when I think about them and post a couple more in addition to this one, in installments of five or so (not to keep you hanging, but because I have a limited amount of time to write each day and because I want to give myself a forum in case I forget things). I'll eventually put these in the sidebar. I'm not necessarily trying to educate anyone in any broad sense, just to produce a little primer about what's going on here that will hopefully be helpful to newcomers. Many of the veterans (and probably many of the newcomers) will find this stuff blindingly obvious, and I don't mean to patronize anyone. I'm going to skip over some things that used to be controversial but that I think most people here agree about at least understand the positions on, such as the reasons why OPS is a better statistic than batting average, but I'd recommend the Baseball Prospectus Basics columns for many of those sorts of things.
1. The Pirates need to build from the inside. Yes--in the past ten years or so, the Pirates' ownership has been guilty of greediness. But, to echo some of the arguments made by commenters in this thread, the team's main problem is that they've never produced a core of young players good enough for their greediness to matter much (except in the case of the Aramis Ramirez trade, when their thriftiness hurt the franchise a great deal). Even given an ownership not as greedy as the team was under Kevin McClatchy, the Pirates will never spend as much as the Mets or Yankees. They can't adopt the strategies of teams who attempt to purchase their core players rather than developing them, because other teams have more money and always will, at least until there's a massive change in the Collective Bargaining Agreement. Besides, by the time most players hit free agency, they have passed their peaks anyway. The one saving grace for teams like the Pirates is that players can be paid well under market value for the first six years of their careers. So the Pirates must develop a core of star players who they can then control for many years. Until they do that, gripes that they're not spending enough on veterans don't hold much water. Any failure on the part of management to spend on amateurs will be fair game.
2. With some exceptions, moves should be judged based on how they looked at the time they were made. Baseball players' career paths are uncertain. There are no sure things, only good gambles and bad gambles. Unless a general manager or team establishes a pattern of consistently seeing things other GM's and fans don't, moves should be judged on whether they represented a good gamble or a bad gamble at the time. Many good gambles over time will produce good results. Anyone who plays poker understands this--you can play a hand perfectly and still be beaten, and that doesn't make you a bad poker player. Similarly, you can play a hand terribly and win big. That doesn't make you good.
3. When interpreted properly, minor league stats matter. Bill James has shown that adjusted stats from the high minors correlate well with big league performance, and thus they should be considered in determining what a player is worth and whether he should get playing time. They must be used properly, however: obviously, the quality of baseball at AAA is lower than in the majors. Also, many AAA ballparks are extreme environments that benefit hitters. Other factors include strike zone control (if a batter puts up impressive numbers with poor strike zone control in the minors, those numbers might not translate well in the majors--think Brad Eldred), age (a 28-year-old putting up great numbers in the minors is less likely to continue to improve than a 22-year-old in the same league), level (the higher the minor league level, the more the numbers tell us), experience (is the player repeating the level?) and tools. Generally speaking, though, minor league numbers are important and should not be dismissed. If a player consistently posts unimpressive numbers in the minors, he probably won't do much in the majors.
4. Defense affects pitching. A pitcher has a fair amount of control over what opposing batters do: he can strike batters out or allow walks or homers. None of those outcomes involve the defense (except in rare cases). He can also affect his fate by producing particular distributions of grounders, fly balls, and line drives (generally, pitchers who generate lots of grounders will have an easier time, all other things being equal). On balls in play, though, the pitcher is partially at the mercy of his defense. If that defense is excellent, his results will generally be better; if it is atrocious, as the Pirates' often has been the past few years, his results will be worse. Recent Pirates defenses have ranked among the worst in baseball at converting batted balls into outs, and the Pirates' pitching has looked worse than it is as a result. For more, see here.
5. Fix the big stuff before you sweat the small stuff. Before a team can contend, it needs talent. Until it has a sufficient core of talent, it can't contend, and thus more detailed problems don't really matter much. If the Pirates were to trade Jack Wilson, for example, it would open a gaping hole at shortstop. Because the Pirates are not terribly close to contending, though, it would not matter if the Pirates didn't get a shortstop back. Their best route would be to take the best talent available. They could always pursue a cheap free agent or use an internal option, painful though that might be in the short term. If the goal is contention, the Pirates must first assemble a core of talent good enough to make it to the playoffs. Once that's done, they can mold that core into a team. This is the plan that Tampa Bay pursued: until 2007, they looked to add talent even if that meant logjams in some areas and defenders playing out of position. With the trade of Delmon Young for Matt Garza and Jason Bartlett and other moves in the 2007-2008 offseason, they molded that talent into a real team. See here for more information.