Like every opinion that might run totally counter to "ours" (I WAS in the same boat as you as a Reilly fan), our initial response is to diminish points made, ignore good points, and characterise them as a minority and introduce a strawman - all as you did here.
Not going to pile on you because again, I really like Reilly (thought he should've been mae captain way ahead of Tavares) and enjoy his game, knowing that he isn't ever going to be in that true top tier of defencemen, he's sort of the best of the next group I'll say. But yeah . . . time goes by. Things change. Players evolve, as does the game.
Giordano has indeed shown us something, and you make a good point against yourself when mentioning him as a compareable . . . yes, of course we compare the two, when Rielly is out and a very old Gio takes his place . . .and performs better and makes the team better than him. Of course! We should make those comparisons.
High end of Giordano was a Norris trophy winner and top d-man in the league . . . at his current age and speed, he shouldn't be better than a peak Rielly. But he is. This is in fact noteable.
We need to realise that Rielly is a very good pp defenceman, an overall very skilled d-man with very little physicality in his game (although not devoid of it obviously), and if AS A TEAM we want to get better . . . we need an upgrade onhim AS OUR TOP DMAN (with or without gettin grid of him, ya dig?)