Looking at BKC's tier list, there's a few listings that I would argue.
Keep in mind this is 1. my first post (^w^) and that my competitive knowledge is somewhat small.
Recommended Adjustments:
Tentacruel: B- to C
I can't see the use of Tentacruel due to just being outclassed in most roles. As a specially defensive wall, I feel that Milotic does a better job, or Blissey as a non - Water type. I think the only uses it could possibly have is as a Toxic Spikes setter or as a specific counter (one of which I can't think of off the top of my head :P). Furthermore, its weakness to common types such as Psychic, Electric and especially Ground (being mostly physical as opposed to Psychic or Electric) leaves it even worse off.
Dusknoir: D to C- or C
The one thing I see that Dusknoir has that I could see as being competitively viable is as part of a core containing a Normal type wall (Chansey/Blissey, Snorlax, or even Wigglytuff). By having an immunity to Fighting types (which are supereffective against Normal types) and Normal types being immune to Ghost types (which destroy Dusknoir obviously), would work pretty well IMHO. It has access to Shadow Sneak, a decent Attack stat, and good defensive bulk in both Def and SpDef. However, the reason I recommend it to C is it's general outclassing. As a tank, you need max EVs in HP IN ANY MOVESET because of its terrible HP stat (for a tank). Also, Dusknoir's speed (barring Shadow Sneak) is also pretty low, leaving it outsped by pretty much everything else. Overall, Dusknoir is outclassed in many ways by other Pokemon, but has its niche role as part of a Ghost/Normal Tank/Wall core.
Metagross: A to A-
The main problem I have with Metagross is both good and bad. It's incredibly varible moveset makes it great as a counter to many common threats in DPP OU, but can only be a coutner to several at a time. The 4 Move Syndrome really bugs me; like Bullet Punch has priority, while Meteor Punch packs more power but could be KO'ed before being able to use it. Offensive Metagross can be outsped (even with Choice Scarf), while Defensive Metagross has weaknesses to common types (Fire & Ground). The fact that it can be a great counter DEPENDING ON THE ENEMY TEAM makes me want to lower its status slightly, as it doesn't have a specific role but still make it on a competitive team just as it's overall great niche filling to be whatever your team need. Don't get me wrong, I love Metagross. His great stats, awesome ability in Clear Body and versatility is really good, I just don't see him in the top Pokemon in the A tier.
Ninjask: D to C or C-
I have the same opinion on Ninjask as I did with Dusknoir; it has it's niche role in a team. As a very fast Baton Passer, Ninjask can be a good lead to pass it's stats along to a physical sweeper. Its passive Speed Boost gives it +1 to Speed every turn, and it has access to Swords Dance. A set with Roost, Substitute, Swords Dance, and Baton Pass has it's uses. However, Ninjask's 4x weakness to SR and terrible typing leave it only this niche role. It's also terribly fragile, so to run it as a lead you'd have to max HP EVs as well as either Attack, Speed, or Def/ SpDef. Despite this, Ninjask being able to pass Speed and Attack boosts while Roosting behind a Substitute can make it a great Baton Passer to a physical sweeper like Scizor, Lucario, Infernape, etc. is very good in the lower tiers of DPP OU.
EDIT: BKC, if you could elaborate on Empoleon's competitive viability it would be much appreciated. Empoloeon is arguably one of my favorite Pokemon in my favorite competitive game tier (DPP), so I'd love to see a couple movesets with EVs and items if you're willing.
