Slightly overstating Rory's awesome. But only slightly.
Rory is one of those characters who snuck in to being a hero. From a gaming perspective, does he work by the DWAITAS rules? It looks like an NPC turned PC with some judicious use of Story Points. He certainly seems to have bought off an early Unadventurous trait (as well as several cases of Lethal damage) as well as a possible skill upgrade from his time as an immortal Roman Auton, all while retaining his sense of “is this really a good idea?” when Amy’s Impulsive and Insatiable Curiosity get the better of her.
He’s also a good example of group character creation, or adding to an existing group by building on previous connections. If a theoretical game started with the Doctor and Amy, a typical addition would be another companion type, but adding Amy’s future husband is something Amy’s player must be cool with, or maybe suggest herself, as it affects her significantly.
(As for Melody, pregnancy and parenthood is not something one drops on a PC lightly or without the player’s agreement, even if the PC is only effectively pregnant for a session it will change how they’re played from then on. And River, I’d suggest making sure the players wouldn’t mind a big possibly emotive plot twist...)
Despite this, Rory is still sidelined in some spinoff media. He hasn’t yet appeared in the Doctor Who Magazine comics (except in an imaginary story) and doesn’t have an action figure even though they made a non-specific Roman. But I’m sure he doesn’t mind. If he did, he’d destroy the universe with his bare hands and make a new one where he gets an action figure.
Game-wise, that might reflect his on-off appearances in his first series, before Arthur Darvill got his name in the credits. Maybe his player couldn’t make every session... and there was going to be a big gap at one point, so the GM and Rory’s player came up with a plan to kill him off and then bring him back at the series finale.
(Did they tell Amy’s player? Good question...)