The treble won't affect many eligible fans choice to go or not long term SC holders and older fans don't need trophies to make them turn up
new signings may encourage some I will agree with you on that
playing arsenal an extra time has zero appeal to many, having to play the wankers at all is bad enough and a big reason I was 50/50 before the time anouncement, honestly playing the tarquins means fuck all to me, rather it was by invitation and we chose someone interesting to play.
the venue, day and time are the reasons for a boycott suggestion, but other factors will also put some off with such a long season ahead after it
The cons outweigh the pros imho