Comment # 11 on bug 1205407 from Eric Levy

Please note, the request is not to change the default size, only the minimum
size, that is, to allow the user performing the install to select a size
smaller than the default.

EFI partitions are routinely created with sizes of 100M or smaller.

The overwhelming majority of systems receiving an installation of a Linux
server will hold only Grub in the EFI partition, not non-Linux boot loaders nor
Linux kernels.

Adding an advanced option with a warning is unlikely to be harmful for
inexperienced users. As variously stated, the partition size is extremely
difficult to change once chosen. Unlike other default install options that may
be changed on the active system, partitioning is essentially permanent.
Providing no option in the installer ensures that even advanced administrators
are prevented from defining an system appropriate for their needs.

Inevitably, some administrators will manually adjust the partition arrangement
after installation, which includes shifting all data from the main partition,
if the allowed options are not suitable. Such cases will generate considerable
frustration, due to the installer not accepting the desired choice.

Providing an advanced option accompanied by a warning would appear to offer a
sensible compromise.