The awesomeness that is anti-Erufuun/Shanderaa/Heatran Blaziken:
Blaziken @ Lum Berry
*the anti-anti-lead*
Speed Boost
Max Spd, xxx Atk, xxx Satk (+Spd, -Sdef)
- Nitro Charge/Fire Spin
- Hi-Jump Kick/Double Kick
- Stone Edge {Set 2: Earthquake}
- Overheat/Fire Blast {Set 2: Hidden Power [xxx]/Stone Edge}
A direct threat to any Erufuun without Gale and counters scarfed Shanderaa/Heatrans that switch in to abuse Flash Fire. Turn 1 is always Nitro Charge, if it hits anything, Blaziken starts the next turn with +2 speed.
If Erufuun stays in, it's taken a hard hit or sacrificed a sub for nothing but seeds... and Blaziken starts the next turn at +2. If Blaziken IS seeded, Double-Kick (overspecialized gimmick option, i know) will smash the sub and start putting a STAB'd beating on SubSeeding Erufuun. Stun Spore is handed via Lum Berry once.
Encore on the second turn is no threat to Blaziken, since that gives it another turn to smash Erufuun with a STAB'd supereffective hit before switching out. I don't know how many Nitro Charges it takes to KO Erufuun with seeds on Ken, but probably no more than 3.
If Scarfed Shandera switches in without Ken under Encore, it's best chance vs. Ken is a speed tie and Hidden Power xxx while it doesn't want to take an Stone Edge from Ken. Another turn, and no speed tie exists. If Heatran switches in, +1 Ken will always outspeed it. That eliminates Erufuun's two most prolific partners.
Set 1 (Stone Edge and Sp. Fire) is for endgame wallbreaking coverage and handling Urugamosu, while Set 2 forfeits endgame coverage in order to guarantee KOs on bulkier Heatran and a random gimmick pokemon of choice (Gyara, Pert, Sala-Nite-Flygon). While HJK can be used either way, Double Kick can't be used without Set 2, or Heatran's an issue.
Now, the problem is obvious: This Blaziken can't ohko everything. Almost everything can ohko this Blaziken. This Blaziken packs a lot of power and decent enough coverage, but wont be ohkoing most of the things it covers. It'll want to escape and hide until midgame to break walls and tactically eliminate weakened stall threats. Which means Blaziken wants to get out of it's lead role without losing too much HP. It absolutely hates things like Machamp leads for this reason.
Ditto's another issue. You'll never beat it switching in unless you're using Nitro Charge, HJK, or EQ. Beating a revenging Ditto is improbable.
As for EVs, while it's possible to run less than max Spd (no speed at all would still be unbeatable by unscarfed base 100s at +2, a stat of 214 beats scarfed Shadow Tag Shanderaa at +2), doing so puts Ken at risk of losing a speed battle vs Scarfed Flare Fire Heatran and Shanderaa.
