I would like it better if the Interludes/Rank up of Servants forced you to use that Servant in your front line for the battle. Even if it was a class that had an advantage over you. Just to test your mettle with overcoming that challenge. Plus, I think it would fit in better with the story of that particular Servant’s Interlude that you are utilizing that Servant in the battle. Just my 2 cents.
What do you people think?