English Translation
I think that style of dress will return again next year.
見られるだろうと思う is very wordy and redundant. It’s like “I think I guess that it will be…” in English. It should be either 来年も見られるだろう or 来年も見られると思う.
But still ドレスのスタイル + 見られる sounds a bit unnatural although it’s understandable. My alternative translation is:
あのドレスのスタイルは来年も流行るだろう。（はやる）= (Lit.) The design of that dress will be continuously in style next year.
見られる in the original Japanese sentence means “to be seen”, so it doesn’t tell that the design of that dress is currently in style and many people want to wear like that, nor the trend will continue. It is more likely to be interpreted as “some, not so many, people may wear like that”.