The problem with a mantle is that it is always comparing itself to itself.
Every Robin is judged based on the best qualities of all the other Robins. Jason was defined as either a "Grayson wannabe" Pre-Crisis or as someone totally different from Dick from Crisis until his death. Tim was originally "the Robin with living parents" and a reaction to Jason's bad-boy image. someone putting on the Robin mantle in 2222 will be defined in terms of what he shares with all the prior Robins and what he brings to the role.
Very few people are going to call out Green Arrow for not living up to the standard of Bruce Wayne despite the "Batman with a bow" description, but if Oliver had actually called himself "Batman" ....
Impulse had his own identity that got lost when he was turned into "Kid Flash" or worse yet "Flash 4.0".
And for good or ill anyone calling themselves "Superman"- be it Jon, Conner, Kenan, or Craig King- is going to draw more comparisons to Clark than someone calling themselves Mon-El, "Iron" Munro, or Hyperion.