I don't want to be able to invite players while engaged. It gives power to n00bs and retards. I remember the horrors of XI's early days (before rage timers) where LSs would bring 30+ people to Fafnir and zerg it dead in a 5-6 hour fight because they could just keep throwing people at it by booting the dead.
Rage timers prevent that somewhat, but it still makes shit easier for those who don't wish to learn a strategy. Dodore was a hard NM for most LSs on my server back in Jan for example. If they could have booted their dead tanks and added new ones they'd have zerged it dead no problem.
Right, easy solution to satisfy both parties. If the mob is an NM, don't allow invite while engaged, otherwise allow it. It's probably just the easy mode people who want the power to boot their dead and invite others. I've no problem wiping to an NM because half the party DCed and it has happened. It's a price worth paying to prevent the shit XI had.