To be honest, I am not used with Sentai roll calls similar to Goseiger. In case you don’t know the usual roll call here it is, the Red Ranger will first do his introduction then the Blue and Green/Black then the Yellow and Pink/White. But in Gosei, It was Red, Pink, Black, Yellow and Blue. There is a similar case in Gekiranger but it was easier to digest. There is a lot of time to get used to it.
Since the Gosei Angels are warriors in training, there are some instances that Alata felt that he is not ready to lead the Goseigers. To be exact, when he accidentally lost his Change Card. He is quite an airhead but it is not an excuse to be irresponsible. That is why it felt that Agri or Hyde should lead the Goseigers.
A Card-based Battle System was first used in Kamen Rider Ryuki and Shinkenger had a run on it once thanks to the Decade crossover. A Card System has its own disadvantage and that is, one you weren’t able to insert the card or left the card somewhere, you cannot transform AND you need to summon your weapon via cards. But it has its own advantage, in terms of selling toys, cards are very collectible and in terms of realism, a card-based system is more realistic in some sense.
In terms of story, Goseiger had a potential to create an epic storyline. I mean, Angels sent from heaven to protect humans and the ones on Earth are just in-training? To add the depth, there is an invading alien force coming towards Earth. But the story also reminded me of Fiveman. Fiveman’s story is five siblings who are protectors of the Earth and fighting alien invaders that killed their parents earlier in the series. In Goseiger, if my memory serves me correctly, Agri and Moune and siblings while Alata and Eri came from the same tribe.
Overall, the first episode gave me a good impression to continue watching the series till the very end.