There are some glaring gaps in MAN's short haul network. MAD for instance. BCN, FCO are poorly served and there are only one operator on the MXP now that Volareweb are pulling out. Besides, we don't know what the routes are going to be for definite until they are announced.
MAN lost it's big based airline when BA pulled out. I don't believe that BE has stepped into this role and so BA needs EZY in my opinion. True, LS and TOM have sizable operations but these are predominantly to bucket and spade destinations. EZY, I am sure, will deliver services that benefit leisure travellers and business passengers alike.