Auto attack promotes communication, co-operation, helps with server side lag/latency, and does not pull away from tactical play.

Communication is promoted because you have time to chat.

Co-operation is promoted because Battle Regimens will be much more likely to be used.

By forcing less actions to be entered per second (especially with those players who spam) there will be less lag/latency due to having a server side client. Making the game much more enjoyable and allow actions like Feint to be used in appropriate time windows. Cures can be cast on demand rather than waiting waiting for your stupid inferior attack to finish (much worse if you have several queued up) so you can mass heal if the mob(s) score multiple critical attacks or use very strong TP actions. Normally you would die by the next regular attack of the mob because you can't cast Cure in time due to some issue whether directly or indirectly because of auto attack interfering with mandatory animation delays or lag/latency.

This does not decrease tactical thought put into playing the game. My reasoning for this is because regular attacks are too inferior to really have any thought of judgment over other than I have to be careful not to screw myself over in case I need to use a specific action immediately without any delay whatsoever which regular attacks can definitely interfere with. With or without an auto attack I'm spending the same amount of time considering which actions to use and regular attacks are second nature to me (require no thought process behind to execute effectively like blinking)

I think this far outweighs trying to fix the issue by extending battle queues.