I like the designs of the mecha bodies by themselves, but I have to say my main issue with Thunderbolt designs overall is the overuse of the sub-arms and the complete imbalance of the backpacks (not that it really matters in space, but a few of he ground-type suits are imbalanced somewhat...Gouf notwithstanding since it's a flight system). Besides, the Zeta Gundam era was where the sub-arm system first got really used in canon with mobile suits like the Titan's Test Team TR series and Scirocco's The O.