If you recruit players who have strong mentalities generally, the issue of on-field leadership becomes moot.
The NEED for a strong, inspiring leader is greatest in teams or organisations where the general standards are poor. We have all said for a very long time that there is a noticeably weak group mentality in the Everton squad, and it has remained in place despite dozens of players coming and going over the last few years. A strong captain can alleviate some of the problems temporarily, but all that does is buy you a little time to ship out the weak links and bring in replacements.
Whilst a stronger captain would definitely help in the short term, the more complete fix is to pay more attention to personalities and psychological indicators when recruiting players. Mina, Godfrey, Allan, Doucoure, Townsend all have the "right" mentalities, as far as can be established from watching them on the tv. Richarlison has most of the raw materials but can be a bit immature, and I'd say the same about Digne. Gray and DCL show signs of being made of the right stuff BUT it wasn't that long ago Gray was seen throughout the game as a waster - thankfully he seems to be knuckling down and letting his football do the talking. The rest of the squad though? I worry.