I myself find Deoxys-D quite easy to deal with on my team, it just requires the right team building to keep it from getting up too many layers of hazards. I find the Classic Choice Band Scizor to be the ultimate "check" to Deoxys-D, doing a whopping 82.89%-97.70% to Max HP SpD variant, pretty much a OHKO with rocks or Sandstorm. However, the problem is Deoxys-D Leads, which I find incredibly annoying and overwhelming at times. Mixed Genesect can also 2HKO it at +1, however it then again requires another powerful hit to take it down. With the combination of Genesect and Scizor, Deoxys-D is only limited to one layer, however having to build a team with these two members on it just to deal with one Pokemon is a bit redundant. I definitely can't wait to see this thing in a suspect test, because the ability to wall most of the meta game on top of being able to defend itself with it's decent attack and speed is a bit scary to go up against. I think Genesect is a decent answer to Deoxys-D, however if it ever ends up getting banned that might definitely increase Deoxys-D's usage. I'm interested to see how these future suspect tests effect the meta game.