Some irrelevance here, but you do bring up a good point or two.Have not been playing in a band situation for a few years but I'd toss my opinion here as a food for thought. When it comes down to money, the whole equation gets simple - the best option financially is to have a 1 man band if the audience really needs a "live" experience at all. If you care about logistics, get rid of the drummer and use some electronic gizmo instead. It seems to me that an exercise like "how many band members can I fire before anyone can spot the difference" makes not much of a sense. I know it may sound difficult to achieve but I'd stick to the sound you want to have and then figure out how many players and what instruments you need to have to achieve it. Once you get the sound that makes your band special and stand out, try to convince the bar owners to pay more for the more enjoyable experience. If you don't miss a second guitar much, than I'd ask myself if we utilize the two guitarist on stage set up to the fullest? Think of early E-Street Band - it's the overall wall of sound (aside from great songs and lyrics and the Boss's charisma) that made them stand out. And if managing larger band scares you, get some coaching or reading on team management - it's a skill to be learn, not a thing that should limit your chances to get the sound that's in your head. Think of the one guitar Rolling Stones gig - would you rather decide to manage Ron Wood and Keef, no matter how difficult it might be, or sacrifice the sound for the sake of peace?
I'm well aware of the "individual pay:number of band members" ratio, as well as logistics, etc, and we aren't looking to fire as many members as possible before anyone notices . This is only about saying "the fifth member, and his sub, have issues, so maybe we should just stick with a 4-piece configuration (trio with a female lead vocalist) and call it a day.
Before I address the good points you made, I should probably update my original statement.
Since writing my OP, the young guitarist has removed one of the irons he had in the fire that automatically out him out of commission the minimum of every other month due to travel commitments. Since that change he has seemed to have a renewed interest in learning new material with the band. But he still has about 5 other projects going on, and they will eventually interfere with our band gigs.
The keyboardist played with us on Friday night and Saturday afternoon. Friday night we also had the 2nd guitarist with us. That was the first time those two had met. First off, 6 pieces created some difficulties, but that was primarily because we weren't rehearsed. He didn't sing because he didn't need to with the young guitarist/singer there. It also increased the volume when needed to keep it down. At the end of the night the other guitarist said that he would just play acoustic guitar if all 6 of us play together again. But after that gig I doubt that all 6 of us will play any future gigs.
The keyboard guy played okay Friday night, but he played kind of bad on most of the songs Sat afternoon, and really butchered a few... and barely sang a word, probably because he had lost all confidence in what he was playing and couldn't release any brain cells for singing. So much for his good harmonies. He sounded pretty good at rehearsal on Thursday, but that all went out the window on a gig. You would think that someone who has been playing as long as he has wouldn't suffer from severe stage fright, but that seemed to be the case.
"stick to the sound you want to have and then figure out how many players and what instruments you need to have to achieve it"
That' not really possible because it isn't as though we have a catalog of available players that can fit in with us, or would want to. So we have to have to work the other way around - who and what instrumentation do we have available (and they have to be people we get along with), then choose material that fits our vibe and works with that config.
As I read all of the replies, and assess how our band gigs have been going, I'm starting to form the opinion that we should stop using the keyboardist after he fulfills his gigs with us this year, unless he shows a complete turnaround in his confidence and ability to play to our needs.
I'm also beginning to think that the 2nd guitarist should be relegated to acoustic guitar only. One of his faults (IMO) is that he still plays like he is in his old college trio where he never adjusts the volume on his electric guitar. It's always cranked at full gain. At least when he's playing acoustic, his playing falls to the background or comes to the foreground based on the dynamics the rest of us play with.
As for simple 4-piece vs expanded 5-piece, we may just work out a list of songs that we can play confidently as a 4-piece (which is almost anything), then use the other guitarist when he's available.
I don't want to manage anything except my own playing and vocals . The others in the band have to manage theirs, and we should all manage to work out songs to our satisfaction together. The last thing I want to do is to tell someone else how to play their part so that it fits with the song, the style, the dynamics, etc. They need to be able to figure that out on their own.