Malone is the much better defender right now, which isn't surprising given his experience in this league and Sessegnon's age. The great thing about Malone is that he's been decent going forward too, which really nobody could expect. He brings lots of pace, energy and work rate down the left wing. It doesn't always look pretty, but his crosses and long shots are decent too. Watching our opponents' left backs, it's evident that Malone is one of the most complete left backs in the Championship right now.
Jokane found the right mix between Malone and Sessegnon until a few weeks ago. Then he got too cute, although I like the option of Malone AND Sessegnon in our starting XI. Should we sneak into the playoffs, I'd rather see Malone at left back.
Sessegnon isn't the best defender and will probably never be. That's just the direction the game of football is heading. Young Gareth Bale wasn't a great defender. David Alaba isn't a great defender either. But they offer so much going forward, and put so much stress on a defense, that it outweighs their deficits. As for playing Sessegnon as a winger, he can undoubtedly do it at a high level, but he is much more dangerous when overlapping from behind. Wingers are dime a dozen. Kebano, Ayite, Aluko are among the best in the league. But it's really hard to find a left back that has great technical ability. Most PL clubs don't even have a decent left back. It's arguably the thinnest position in football - hence the reason why Sessegnon is so highlty regarded.