It's very convenient to set root password and other options while running MariaDB Setup for Windows (much more convenient than "MySQL Server Instance Config Wizard" for MySQL). Just options really needed, no extra rare stuff. But, no server character set selection.
I think you understand, but I will shortly describe problem: some software, developed for worldwide (not for one country) prefer to use utf8 for saving all data and for all countries. Latin1 is right choice for such software only for most of Europe and USA. For .NET software (as far as I know, may be for some other) setting only "character_set_database=utf8" leaving "character_set_server=latin1" cause some troubles (and anyway make to set encoding for each new database manually).
On my position I install MariaDB several times a week (mostly on Windows) so option to set "character_set_server=utf8" in installer will make life of mine and other people installing MariaDB regularly a little easier.
(In this case pressing "Finish" in installer does not require changing config, restarting server etc. - 5-7 minutes to do)

If you prefer not to overload installer (but I think it will be a great option) may be it can be done as command line option for installer (but I think it's not so obvious and convenient).

Thanks in advance.