Thing is, when you only want to manage X amount of players for an RP, you need some metric to determine if a player is going to mesh with the group, of their character is appropriate, and in my eyes, if a player is willing to put considerable effort into a sheet and patiently wait for and meet deadlines, then character sheets are invaluable; as a GM, I personally like to draw parts of different characters' bios and introduce them into a plot. It's very important to me that my players feel like the story values their characters and gives them personal story arcs. Sheets facilitate that.

I never liked the idea of fleshing out a character's history over the RP because a) most RPs don't last that long to have that be relevant and b) what ensures consistency? A sheet helps you keep track of important character traits and history. Also being able to write an interesting and fleshed out bio is a good gauge of how a player is for writing for my RPs; my games are very collab heavy and are more collaborative storytelling than a game (current word count is over 500,000 words). I view the CS as a snapshot of a character at the start of an RP, not necessarily who they are going to be the entire duration.

One system doesn't work for every style, so it's a mistake to try and treat all RPs the same, and enforce a singular set of standards for all players. Variety is important. I just know for the past 7 years, I've found what works for me and mitigates a lot of headaches, player drama and conflicts, keeps players engaged and active, and ensures a consistent writing quality and standard for all players. Having a detailed character sheet and a two part audition process is a necessary evil, I feel. The more you can do to mitigate problems and ensure that players are at least starting off at a certain level and standard does wonders to ensure the game has a good chance of going smoothly to the point all a GM has to do is keep things moving along to keep it alive. 

Also, check applicants' posting history; if they have a history of flaking and not staying with an RP for long, you do not want them.