Overview
You need to expand more on Weavile's positive qualities. Elaborate on its amazing 125 base Speed, allowing it to outrun significant threats like Alakazam, Starmie, and Scarftar; that's HUGE. Combine this with access to Pursuit allows it to prey on many top Ghost and Psychic types of OU, namely Latios, Gengar, and Starmie. It's noteworthy that there are many Pursuit users, but only a few handful Pokemon like Weavile can really pull it off effectively / not be a liability outside of Pursuit-trapping. Ice Shard also revenge-kills many dangerous threats, namely Rock Polish Landorus and +1 Salamence.
As for its shortcomings, the lack of high-powered moves to complement its high Atk has to be its greatest flaw, as it struggles to maim Pokemon that it hits neutrally or even super-effectively at times. Weavile especially has a tough time breaking past Water- and Steel-types that are neutral to Low Kick.
I'd like to see all of these information incorporated into your overview.
and the B/W introduced Conkeldurr and Volcarona still pose major threats to Weavile.
Replace Conkeldurr with Keldeo, a much more pertinent threat in the current metagame.
Since the release of BW2, Weavile have often been seen amoungst hyper offensive teams using both Deoxys-D and Gengar.
As jc104 suggested, remove this sentence, since it's rather misleading. Any team that requires Weavile's Pursuit-trapping / Ice-shard / Speed capabilities can benefit from Weavile, not just Deo-D teams.
Set Comment
~ You failed to mention Night Slash and Ice Punch in your set comments. Instruct users the pros and cons of either move.
- Night Slash hits certain Pursuit targets for super-effective damage, such as Jellicent and Starmie, thereby punishing these mons if they ever act bold and decide to stay. Night Slash also allows Weavile to connect Water-types (Rotom-W, Politoed, and Tentacruel) and Jirachi for strong neutral domage.
- On the other hand, Ice Punch is certainly useful for hitting Ice-weak mons for strong damage, actually threatening to KO mons like Hippowdon, Amoonguss, Gliscor, and Landorus-T if they decide to stay. It also punishes Conkeldurr who would otherwise set up on Weavile with ease.
With 216 Speed investment, Weavile can outpace everything necessary in OU, while the remaining 40 Hp investment adds bulk as it takes repeated Life Orb damage. With Tornadus-T now brande Uber, it only needs but 216 Speed EV investment to fuction effectively in battle.
Specify what the Spread allows Weavile to be faster, namely Alakazam and anything slower (including Starmie, Latios, and Tornadus). Also remove the sentence about Tornadus-T, it's unnecessary.
Low Kick rounds off Weavile's needed coverage, while also ensuring that it is not restricted to only two base 40 power moves; Pursuit and Ice Punch.
- You meant Ice Shard here, not Ice Punch.
- Also you can definitely expand more about the usefulness of Low Kick. It's a major boon to Weavile's otherwise limited physical movepool, allowing it to lethally maim Steel-types, namely Ferrothorn, Heatran, and Magnezone. It's also a coverage move essential in nabbing quick and easy KOs against Tyranitar, Terrakion, Mamoswine, and offensive Kyurem-Black (after SR)!
Other Options
~ This section comes AFTER Additional Comments, so please swap the position of these two sections
~ Add that Focus Sash / Ice Gem / Dark Gem / Fighting Gem can pair well with Weavile's Pickpocket ability.
Punishment is an option over Ice Punch and Night Slash if your team needs some extra help in taking down bulky Calm Mind users. CM Latias, Reuniclus and Jirachi are but a few examples that come to mind when considering Punishment.
Nah, Punishment should never replace Ice Punch / Night Slash; they are necessary for reliable damage against non-boosters. If anything it'll replace Pursuit.
Checks and Counters
~ This section is unorganized - break different types of checks and counters into separate paragraphs. Defensively bulky mons that counters Weavile should be in one paragraph; and faster checks via Scarf or priority should be in another different paragraph.
Such scarf abusers include, but are not limited to, Jirachi, Terrakion, Heatran, & Gengar.
Remove Gengar, since it must rely on Focus Miss to revenge-kill Weavile (plus a weakened Gengar is prone to Ice Shard KO). You can replace it with a more pertinent Scarfer like Keldeo.
Ninetales is a relatively safe switch-in too, as are other less common Fire-types, such as Arcanine.
Remove Arcanine; it's irrelevant in OU. Ninetales also does not enjoy taking Night Slash. Only Infernape and bulky Volarona are relatively safe Fire type switch-ins.
EDIT: I initially had Heatran, since it resists both of Weavile's STAB moves, but I removed it as per Lord of Bays's input