I think Stackpole's theme is less about loosing identity and more about finding identity. To quote a favorite Sci-Fi series of mine, "In the right new environment, you'll thrive."
Phelan Kell never really fit in among his peers in the Inner Sphere. He was always mouthing off, getting into trouble, going his own way and doing his own thing. Ironically, this rebellious spirit finds himself among the Clans, where one would think the rebellious wouldn't last long. However, Phelan rebels to follow the dictates of his conscience, doing what he believes is best, and ultimately the Clans reward results. Phelan gets results, so Clansmen kind of stop caring how he does it. And the "Might Makes Right" society of the Clans, you lead by proving your worth as a warrior. No one's going to second-guess Phelan because he clearly knows what he's doing (he gets results) and he might kick their asses.
Victor Ian Steiner-Davion always knew he was destined to lead the Federated Suns, but he had to learn for his own how he was going to go about doing that. He had to learn to put aside who everyone else wanted him to be and learn to be himself alone. He had to reject the path of his mother the Peacemaker, his father the Magnificent Bastard, his potential grandfather-in-law the Noble Samurai, and everyone else's assumption that he was either an egotistical hothead out to prove himself or a spoiled brat who expected everything to be done for him. Victor had so many premade identities laid out before him, he had to pick and choose the best parts of them to forge his unique identity.
Kai Allard-Liao. Oh, where to begin? It's outright stated when we meet him how he feels the burden of living up to what's expected of him is crushing him, and how he's absolutely convinced he's just not good enough, not smart enough, and doggone it, people don't like him to be the great warrior everyone knows he is. He honestly, steadfastly believes everything he tries will ultimately end in horrible, fiery failure. He has to be almost literally clobbered over the head with the fact that not only is he just as good as everyone says he is, he's in fact even better. He has to learn to let go of his self-doubt and self-loathing and consciously accept the confidence necessary to truly fulfill his insane potential. Like Victor, he needs to become who he should be regardless of the outside influences forced upon him, but unlike Victor, Kai's conflict is almost all internal, with his challenges and demons all springing from his own mind. The exterior conflict of Victor's multiple potential identities is mirrored in Kai's internal struggle with his own inferiority complex.
Interestingly, Hohiro Kurita is less of a main character, and rather a supporting character for Shin Yodama. Similarly to Kai, Shin is very humble and credits luck and others far more than himself, but it's quite clear he's an exceptionally capable warrior. The major difference is that while Kai's humility stems from his inferiority complex, Shin's comes from a genuine desire to place credit where credit is do, not overestimate his own abilities, and to live up to the standards of proper behavior within the Combine. But here is where Shin's quest for the "right new environment" comes up. He's yakuza, a barely-tolerated element of Combine society, yet he's also a MechWarrior, the very pinnacle of warriorhood his warrior people aspire to. He must learn how he fits into the rigid structure of Combine society under this duality, and must carve his own niche where one does not exist. Because of his genuine desire to live up to and serve the principles of the Dragon, he does this behind his polite, unassuming facade, neither forcing others to accept him on his terms, nor allowing himself to be dismissed because of another's preconceptions. His is the tale of not merely finding the correct identity, but creating one from whole cloth because what you are is so outside everyone's expectations they have no frame of reference for it. As with many things about Combine society in Stackpole's books, this is presented so bluntly yet so subtly it's very hard to pick up on unless you're looking for it.
Characters like Sun-Tzu Liao and Katherine Steiner have to decide which identities they will craft for themselves to achieve their goals. Sun-Tzu hides his brilliant scheming behind a facade of madness to get others to underestimate him, while Katherine hides her scheming insanity behind a facade of gentle kindness to get people to underestimate her. The discovery of not just one's personal identity, but what perceived identity will best benefit it. A double-whammy.
Even the Clans as a whole are on a quest for identity. The driving question behind the Crusaders, one they dare not admit even to themselves, is "if we are not the restorers of the Star League, what are we?" The Wardens have an answer, but the Crusaders don't like it.
This metaphor becomes very clear with the addition of the Clan totem masks worn at the Clan meetings. A mask not only hides your identity, it presents a new one to all who look on you. The Clansmen who wear their totem masks adopt the identity of their Clans themselves, becoming one with it, speaking for it, making decisions for it. But behind the mask the person is still themselves, and must still obey the dictates of their own conscience, whatever they have decided those must be. Note how Ulric, Natasha, and Phelan rarely, if ever, wear their masks, and note that these are the strongest and most confident of the Clansmen, the ones most assured their course is correct (and the ones the reader is meant to most strongly sympathize with). They refuse to even pretend to subsume their identity into that of their Clan, because they are keenly aware they always decide matters of great import to the Clan. That responsibility is no mask one can take off and put on at will, it becomes the fiber of one's very being if one is to be a truly great leader. Note also how Phelan adopts Clan speech and mannerisms, attempting to fit in, while Natasha, raised among the Clans, doesn't care if people are upset by her contractions. Both are imposing their discovered identity on the Clans themselves: Phelan by showing them someone from their Inner Sphere can "beat them at their own game," Natasha by showing them that "corrupting" influence of the Inner Sphere has no bearing on a warrior's skill, determination, or intelligence.
