Genesect has received a large amount of nerfs this Gen. Ho-oh is arguably the biggest threat in the Metagame and apart from relatively gimmicky moves like Thunder and HP Rock, it can't do crap to it, while Ho-oh can easily finish Genesect off with a STAB Sacred Fire. The Steel nerf means that it can't switch into the match as much as it could last gen, which is especially notable against threats such as Mega Gengar, Yvetial, and Darkrai. It's Choice Scarf set can't check Speed boosting threats, such as Mega Blaziken and Geomancy Xerneas and is setup bait for threats such as Mega Gengar and Substitute Ho-Oh if locked into the wrong move. Mega Scizor also gives Genesect a large amount of competition this gen thanks to its larger amount of Utility with support moves in Defog and Roost, better overall bulk and Attack, and better priority move in Bullet Punch.
Despite these nerfs, I still believe Genesect will be very viable this gen. Its Choice scarf set still makes a decent check to Mewtwo-N and-Y, Darkrai, and weakened Arceus-N, as well as newcomers such as Non-Geomancy Xerneas and Bulky SD Mega Scizor. Its also still very versatile, with multiple sets ranging from Choice Scarf, to Expert Belt, to Shift Gear. Overall I still Genesect will be a threat, but not a major one like it was last Gen.