Viewing Dark type Pokemon and the dark type itself what would you classified it's greatest strengths and weaknesses to be?
Like what AWsquared said, the greatest strengths of the Dark-type is their high Attack stat and the fact most learn moves that abuse it well. The fact that most fully-evolved Dark Pokemon have at least 100 in some of their base stats makes them pretty strong, and the fact they can counter Psychics well due to being immune to Psychic attacks. Most Dark-types do tend to lack defenses, but some notable high defensive stat Dark-types include Mandibuzz, Umbreon, Scrafty, Bisharp, Drapion and Spiritomb. Adding on to that, most Dark-types tend to get a secondary type, so far they've combined it with Dragon (Hydreigon line), Fighting (Scrafty line), Flying (Mandibuzz and Honchkrow lines), Ghost (Spiritomb and Sableye), Grass (Cacturne, Nuzleaf and Shiftry), Ground (Krookodile line), Ice (Weavile line), Poison (Skuntank line and Drapion), Rock (Tyranitar), Steel (Bisharp line) and Water (Sharpedo and Crawdaunt lines).
Also, there's loads of tricks involved with most Dark-type attacks, and while most Dark-types are physical attackers, there are a few Special-based Dark-type attackers too such as Hydreigon, Zoroark and Houndoom. It's also only got two weaknesses when unpaired, which is kinda neat despite one of them being the common Fighting-type.