Aren't the "epic" souls supposed to do exactly that - giving 4* guaranteed with no chance for a 3* , but also no chance for a 5*
That's how I understood it.
This said I don't know yet what to do with them. Shall I see tham as sacrifice fodder only or is better to save them until a new 4* character is released (and not only available via event souls) to have a better chance to get the new char (compared to a rare soul). What do you guys think?