[Baertram]

Not interested into creating such an addon as the guild history is shut down for addons already several times and I feel one shouldn't create the next addon to mess around with it and stress the servers.

But a few thoughts:
I doubt there is a way to see if someone recruited a member or are all your guild members allowed to invite someone? And does this count as "recruited" then?
Not even sure if the API tells who has invited someone. Let me check this:
EVENT_GUILD_INVITE_ADDED (number eventCode, number guildId, string guildName, Alliance guildAlliance, string inviterDisplayName)
Yep, could be tracked by help of "inviterDisplayName" as it seems (if this is not the invited user but the invitER).
Anmd here is the invited name then:
EVENT_GUILD_INVITE_PLAYER_SUCCESSFUL (number eventCode, string playerName, number guildId) - Added in 100028
or
EVENT_GUILD_MEMBER_ADDED (number eventCode, number guildId, string displayName)

As one can invite someone and the accept can be several hours later afaik it would be difficutl to track this though as the event data is only given if YOU are online and have the addon enabled at the time the events happen. So if there is no info in the guild history about who invited whom, you don't have the information if you are not 24/7 online.

And in the history you got only something like
"..."joined the guild.
"xxx" invited "..." to join the guild.
So you always would have to connect those two information, even over time, from the history's "text" which would be a mess to do I think.