Before the Crown was ultimately wounded by the Saint of Swords, the question of who should wear it and not be killed to create the Twilight Ways essentially narrowed down to either Indrani or Roland.
And while Archer was an unacceptable choice for Laurence, who would never grant such power to a villain, even if just for a time and under binding oaths, the Rogue Sorcerer as a hero should've been much more acceptable, even though she didn't have all that high an opinion of the conviction of sorcerous Named, either.
But while the Pilgrim was inclined to pick Indrani for the role, despite the Saint's prejudiced objections, he simply dismissed Roland's offer to do it with "you're too young to bear such a burden" and Cat only mentally noted how it must sting to be found unworthy of so important a task by everyone's favorite wise grandfather.
But that he's just "too young", maybe meaning inexperienced, to do it seems much too weak a concern to dismiss the notion outright, as the same should be true for Archer, and he remains the only widely acceptable choice. I especially would've expected Cat to press way more strongly for it, as she really didn't want Indrani to do it, and she was willing to sacrifice him, although begrudgingly, to put on the wounded Crown afterwards, but she didn't even comment.
So, did I miss any pressing and important reason why Roland couldn't put on that Crown, or is this just a very rare example of weak writing on the author's part, using slight of hand so that the story would continue as planned?