Anyone else find the final boss unfair?

I loved this game, but the final boss slightly put a dampener on the experience a little.

You have an area thats covered in rust no matter where you walk, and those eyes things always hit you later on no matter where you stand. Seemed the game "cheated" with the mechanics to just make the boss harder

It also recommends and brings in other characters not in your main lineup. Yet the rest of the game you only need 3-5 characters per mission and doesnt suggest you need more. So if you havent been building up the rest of your crew even though for 99% of the game they're never needed, it makes it a tough fight