I must write this as for me Sagna is one of the best right SB is the world.
I know many won't agree but I will try to explain my so high oppinion about him.
Arsenal is very attacking based team as we all here know that. Their last defensive line is often very far from goalkeeper because so they mantain pressure, combine better and opponents are often confused because it's like everyone in Arsenal could play more than 1 or 2 roles. And role changing is also important part of shaking opponents.
Another reason why they don't play deep is because Sagna, Clichy/Traore/Gibson, Gallas and Thomas, they are all very fast for last line players. And not only that, they do understand the game, tehnique is better than average premiership defenders tehnique and they all have a good teamwork understanding. Their passing is also very accurate and fast enough.
But let's get back to Sagna. He is not that fast and dribbling oriented as let's say Maicon and Dani Alves who are surely best SB's in the world, but that's not the most important task of SB player. Sagna is very good at defending, good at positiong and moving forward ( he lacks cross accurary only ) and most importantly for me, he is great teamwork player always there when there is no one who is free to receive ball. Also he is very good at keeping that ball safe until someone (fabregas , song mostly) arrives and receive a ball.
Sagna's balance is really great, he is better there than Maicon od Dani and that helps him to rarely lose a ball because he get outmuscled or thrown out of balance. I would increase his balance to 86, because i find Song not stronger than him, they are equall and Sagna with 86 balance is not that much more stronger than with balance of 85, but the feeling I get from playing with higher balance suits his style of play better and I'm more satisfied playing with him.
His defense is also very good and his intelligence at positioning is very good for a SB.
I'm trying to compare him with Corluka and Corluka is 80 for me without any question , but Sagna deserves also higher score than current of 76, he could see increase of 2 , so 78 will be the number.
As he is good at tackling is think sliding is nedeed but I'm not sure if you agree.. ?
Second I find him very good at shifting from attack to defense and vice versa.. that would mean he is candidate for reaction, but on the other hand, as that star is rarely given to SB's and I agree that Evra is better in this than Sagna ( but that could be due to Evra's better attack ratio ). I will try him some more with and without reaction and will let you know about my further oppinions about it.
+ sliding tackle ?
If anyone wan'ts to , try him on with my improvements and say your oppinions.