One of the elite talents, but his biggest problem was that his concentration/focus level was UP then DOWN...then UP...then DOWN, over and over and over again throughout a match, throughout his career. In other words, tune in for a few points, and he looks all fired up and playing and moving like his life is on the line, take a peanut butter and OJ (orange juice) break, and five minutes later, the same guy is in a lull, moping, swaying from shoulder to shoulder, looking like he is literally half-awake, sleep walking out there.
Against, Sampras and Agassi; he just didn't match up well style wise. Against Agassi you've got to do something extreme to get him out of his comfort zone, but Pioline didn't do anything extreme, he was just immaculately fluid from all parts of the court and good at everything but not really SCARRY at anything. He was like a well-oiled machine when he was on, all the parts fit together into a beautifully coherent whole.
When he was off or in "one of his moods" he looked and played like the Scarecrow from the Wizard of Oz, all gangly with mismatched parts, AND soul...he played some times like the soul was missing, with nothing to hold all the pieces together.
Against Sampras, Sampras was just too much of a dominant personality for Pioline in my opinion, and also like Agassi, you needed to be able to do something in an extreme manner to make Sampras uncomfortable, but Pioline's game just isn't of that nature. Pioline's typical groundies also tended to sit right in Sampras and Agassi's ideal clock zones.
Pioline's serve while very good was not super sonic great, and Sampras got into trouble playing guys with all-court games only if they had a huge serve of his caliber, or maybe a guy like Edberg or Rafter who could at least kick the ball really high to his backhand (and, of course, the volleys to back them up).
Pioline's performance against Courier in the 93 Open quarters and Stich in the Wimbledon semis and final two set performance against Safin at the French showed what kind of pure talent the guy really had. When he was on, he got into one of his oh, there goes Pioline getting into one of his superman modes again. Well you know what I mean, that's what it felt like when he got all geared up. Laconic Clark Ken suddenly busts open suit with his broad, Ramboesque chest, then takes off up and away without looking back.
Medvedev said he hated playing Pioline, basically saying he was like the worst opponent for him and the guy he hated playing the most similar to Bruguera saying Muster was his least favorite matchup, but for different reasons. Medvedev said that Pioline was so tough for him because he was so very balanced and good at everything, that there was nothing to pick on. Which when you think about it makes sense. Medevedev had similar attributes, but hit a harder, clearner ball on average from the baseline but with less fluidity at net. Just a bad matchup for him, he didn't take the ball as early as Agassi nor go for broke enough from the baseline or serve huge enough to really get Pioline out of his comfort zone. Medvedev's game made it easy for Pioline to settle into a groove in other words. Every player has a certain comfort zone, and as MMA is now showing as the number of top notch competitors grows, the more and more apparent, it's becoming that individual style matchups rather than individual greatness is reigning supreme at the highest levels of the game.