than Rielly?
No. Not remotely close.
Morgan Rielly is a fantastic hockey player that any team would be lucky to have. He's terrific, smart and physically capable and great with his hands. He gets a lot of crap because he has high point totals and he's a Leaf from people who don't watch him. He's absolutely great.
Ghost gets similar flack for the team he plays for and his output, plus the fact he doesn't have nearly the size that Rielly or really any other NHL defenseman have. But he is the better player. I watch huge gobs of hockey every year, and I like to look at things as unbiasedly as I possibly can, and I will tell you that I don't think there's a similar weapon in the league outside of Karlsson. Gostisbehere is one of the best skaters in the league, possesses incredible creativity and a freakishly hard shot for his size/strength (thanks, probably, to light stick flex).
He can handle any pass within 10 feet of him: over his head he jumps to catch, well wide he'll slide and cut it off like a shortstop. There's probably 20 Flyers goals per year that he gets no assist on, but were only possible due to his blue line keeps, and untold numbers of goals against prevented because he keeps the puck from going the other way with opposing forwards charging. The guy's just a pure athlete in every sense. There's no one better at that in the league. The Flyers' good first PP unit is only possible because when someone down low gets in trouble with the puck, they can just throw it somewhere in his general direction and have an instant reset. Not Klingberg, Rielly, Subban, anyone in the league can tame an errant pass up there the way that kid does. Might seem minor, but in terms of a powerplay or preventing transition offense it's incredibly useful.
He's not as good at defending in-zone as Rielly, but far better against the rush (think stick-work, speed, smart dives). And he provides skills that only maybe a handful of other defensemen in the league can even fathom. Rielly is a really, really good 2-way D-man, but Ghost is a very rare breed in this league. Give him a system that isn't so blase and terrible (think of him playing Laviolette hockey) and he'll rip your eyes out of your face with what he's capable of. Just a machine.
It's OK, it's not a slight to anyone.