Yes.

Explain?

Most one piece villains aren't made to be defeated so easily. Almost noone dies in op and villains almost always comeback in the story even if its as allies.

In movies its basically a one and done. Character is introduced, built up, and defeated and never comeback into the story.

If Eneru presumably comes back into the story wouldn't he have haki? Of course, the character would grow. But we'll never see Brynndi World again. But if it was main story character we would see them power up like crocodile

Other examples are smoker, bon clay, koby. Imagine Koby with the more more fruit and being able to use shave with it, or the other techniques

Okay i get you. if he was in the series proper there's be room for more development and reoccurring appearances

Thats imo. Bullet had to be so strong because he came along further into the story. And Shiki benefits from being canon even though the movie appearance wasn't. So however strong Roger is revealed to be, Shiki's power will grow even if we never see him again just by comparison.

I don't put too much stock in Shiki even if he was a so called rival of Roger. He could've put up a much better fight against Luffy given his notoriety. He should've been much stronger

I agree but again I think its like you say about Eneru. The time Shiki was in the story haki and everything wasn't a real thing yet. I think like Bullet, if Shiki and World came later in the story they would've been stronger.

Very true i guess we can blame progression then XD

Bullet easy