I'll now do the pros and cons of each opening.

Ignited:

Pros: Good scenes, music gets you pumped up, Yzak.
Cons: Not the best song otherwise, some scenes that are unnecessarily long and out of place.

Pride:

Pros: Awesome song, great choice of scenes, Heine, cool foreshadowing.
Cons: nothing really

Bokutachi:

Pros: The song showed, just like Believe did for Seed season 3, that things were getting darker
Cons: Seed should never have slow or mid-tempo songs, too many spoilers in foreshadowing

that last song:

Pros: lol
Cons: Everything

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It should also be noted that Pride is one of few openings in history that can rival the amount of times I've seen the opening animation for Realize (Seed op4)