Which is to say... It sounds like the OP inhabits an environment where design is decidedly un-ad hoc (the reference to TLA+ is a dead give-away.) Not everyone lives there. Not everyone approaches design the same way. People dissing the OP should chill. The OP should probably also chill. If someone tells you "you're doing it wrong," just ignore them. People who know what they're doing won't say "you're doing it wrong," they'll say... "Hey, that's different than how we initially thought this methodology would be used... you must have a different environment from what we're used to. Let's dig into this a bit more."
TDD is the wind, it cannot be captured by your net.