I honestly can not comment about Gundam Seed, since I haven't seen it. It looks kinda cartoony and more unrealistic than anything in the UC timeline. If you watch MS Gundam, Zeta Gundam and then Chars Counterattack. Just the relationship between Amuro and Char and how they grow and evolve as people is truely unique to the UC timeline and in my opinion impossible to recreate without it just looking like a shallow rehash. Which are what Seed and the new 00 are.