There should be a invite button for R5s and R4s when looking at others profiles to make recruiting easier.

Have a Standard message that gets sent to the player after you click Invite and on the message it should have a easy join button that the player clicks to join or decline.

I know there is a way to invite players now but that takes a lot of time when you could easily just click on their profile and click invite if you have the rank to do so.

Now if they are with a guild already then the invite button will be grey which means you can't invite them and would have to message them instead.