I think you guys are seriously bagging on about Haxorus's "atrocious" speed. When it outspeeds so many offensive threats such as: Heracross, Lucario, Krookodile, Chandelure, Nidoking, Porygon-Z, Roserade, Toxicroak, Darmanitan, and the scarf variants of some of the scarfers listed when at +1, it can seriously decimate offensive teams. 97 Base speed really isn't that bad in UU. And with all these slower threats that SD set DOES have viability against Offence.
And so what if ScarfDreigon outspeeds by 1 point? It still isn't switching in on Hax at the fear of a potential Dragon Claw to the face which is almost a guaranteed OHKO without a boost. And Mienshao isn't exactly about to switch in on it either. Furthermore, after Haxorus has claimed its victim there really isn't much stopping it from switching out and coming in back later. Both of these Scarfers get walled to hell and back by Phys.Def Florges and Aroma, as long as Haxorus is placed on a Balance/Bulky Offence team, and then Hax can easily come in later, whereas there are next to no safe switchins to Haxorus, especially if it is running the 3 attacks (which is much more viable than what has been given credit).
Its bulk is also being undersold. It has some quite good setup opportunities against bulky Water-types, especially when holding a Lum Berry. Is good against the Fire-types: Victini, Darmanitan, Entei and Arcanine. Blissey too can get setup all over. And as shown in some of the calcs on the previous page, it takes on priority quite well.
And lastly, it doesn't need a boost to deal damage. 147 base attack is quite freckin' strong people. It doesn't need a boost to KO a lot of Pokemon. I've even been thinking about running a CB set, and will get around to it to see how it works, because I have a feeling it will be rather devastating.
Honestly I find this thing worse than Salamence, and if Mence has to go I'd hope that Hax goes too.