A good frontman is everything. If you have a GREAT singer you can certainly get by if they have zero frontman ability because of their pipes.
If you have a good singer who just stands there and the other choice is an OK singer who lights up the room?
Every audience will love the OK singer and have more fun at those shows.
My opinion is the most important thing will always be the songs. There are never enough great songs and more than enough who can sing. This is why shows like The Voice exist and also why winners of the show disappear.
The show is super fun when you have outstanding and good vocalists singing great songs.
Once that vocalist is on their own and the quality of their songs is never as good as on the show? Well, middle America just says, "NEXT" and is ready for the new season of again capable vocalists singing great songs again and then rinse and repeat.
So, great songs are more important than anything else followed by a frontman. If you have good/great songs and a good/great frontman you can ride off into the sunset with average guitarists, bassist and drummer because you guys are mining gold. Ok, maybe not gold. Those days are pretty much done but you will earn and "make it".
Frontmen are super rare. Vocalists are not. This is why Idol and X Factor and The Voice have long lines of people with vocal chops. One look at YouTube and you will find plenty of guys and gals with vocal chops just like there are guitarists for days.
This then goes back to great songs because that vocalist you found on YouTube ALWAYS sounds better when it's a song that is great. Now take that great vocalist and put them on a stage in front of a live audience and they'd better have virtuoso chops if they are just going to stand there and not put forth any energy.
David Lee Roth is the perfect example of good enough vocals paired with once in a lifetime charisma and true frontman ability. Chris Cornell certainly was the better vocalist and definitely a rock star but Cornell never captivated as many people as Roth did and still does.
Robert Plant is a true frontman only he has the chops to go with it so in Plant you had the PERFECT rock n roll frontman. Michael Hutchence was a perfect frontman and he had charisma to burn which was why INXS could not go on because Hutchence was so irreplaceable. JD Fortune had charisma and was good enough vocally but he just didn't have that little bit more of what Hutchence had and as a result he fell short.
You can always find a better guitarist, better bassist, better drummer, better singer, write better songs, get better gear and all of that will improve your band considerably.
But a frontman and a true one at that is worth their weight in gold which is why LSD (Lead Singer Disease) is a real thing. These guys are the stars of the show and they know it and even if their chops are not what the other members of the band possess, everyone in the band knows that without that star they don't have a show since the frontman is what separates them from a billion other bands jockeying for stage time.
I am a stand up comic and in comedy this is absolutely true as you can have someone with the best material but if they lack charisma and cannot deliver it well, they just won't get over.
On the contrary, you can have someone with hack material but if they have charisma for days and perfect timing and just star making delivery?
Well, look at Andrew Dice Clay and Dane Cook who have both sold out Madison Square Garden and gone platinum while you have some comics like Patton Oswalt or Jim Norton who still play clubs.
Frontmen make the audience pay attention to their every single move. This is also true for another industry I have worked in which is pro wrestling. You can have someone who is ripped to shreds and can wrestle move for move better than anyone else and if he can't cut a promo or come out of that curtain like a star it means he will be putting on 5 star matches in the local gym while the guy who "can't wrestle" sells out stadiums.
See Hulk Hogan.
So, yeah, a good or great frontman is so important in a band that it will make the difference in you playing the local watering hole every Saturday or being in demand everywhere else with a following that is far more than your friends on Facebook who come out to see you weekly.
The average patron of live music is not looking to sit on their hands and listen to audio perfection with the greatest of tone.
They are looking to have a good time and that is exactly what the frontman brings to the table. They are the show and when that light is on them, the audience is not busy checking their phones unless they are livestreaming it to show everyone else they know just what they are missing out on by not being there.
Sorry for such a ridiculously long winded rant but I am an ardent believer in what charisma and starpower can do and it damned sure means more than the stuff we focus on as bass players such as string gauge and our tone.
Nobody will deny Michael Anthony's contributions to Van Halen but while Eddie was the once in a lifetime talent, it was David Lee Roth who made them larger than life.
Because Gary Cherone just couldn't fill those same shoes and Eddie alone was never enough as fans and casuals always wanted to know just when DLR was going to come back.
Why?
The importance of a frontman can never be overstated.