As a new user of MariaDB (and an on and off user of MySQL and *nix/Linux), I did find that "mariadb Ver 15.1" jumped out at me and confused me a bit. But "Distrib 10.11.2-MariaDB" was sufficient to assure me that I wasn't daydreaming..
I feel that most users (even DBAs) of MariaDB have no direct need to think of mariadbd. They are not expected to interact with mariadbd directly, but rather systemctl mariadb start, service mariadb start, etc, so when they see mariadb, they would naturally associate it with the server.
In a way, one could argue that it's "unfortunate" that the name of the client is the same as the database. e.g., sqlplus (oracle), sqlcmd (sqlserver), psql (postgresql), etc don't have this "issue." But it's neither here nor there..
Anyway, adding the verbiage "client" is a very good idea to clarify that this is a client tool. It should definitely help decreasing confusion amongst inexperienced users.
I think it's a really bad idea to remove the independent version number from clients:
There are some packages that has changed all tools to just print the package version, like net-tools, gzip, coreutils. However this is not a good reason alone to change things.
I don't think we (MariaDB developers) have any information of what users things about client/tool specific version numbers. Instead of doing a change based on one single users post, we should at least do some studying of the issue. Why not do some information gathering among our users to really understand what they think?
We could do a questionnaire on the MariaDB foundation pages for example.