If you guys are thinking Blood Mage & Witch Doctor need buffs, you seem to be a little mistaken. Heroes that currently need some magic to happen to them at Phantom Queen, Disciple, Pirate, and Inquisitor.
BLM & WD currently dominate their lanes immensely, and work insanely well on the side lanes. The issue that you're probably facing is that you aren't abusing their pushing power to their fullest potential. Utilizing the tower/experience denial mechanism, you can easily get a few levels up on your opponents on BLM/WD, which is part of a successful strategy to simply overwhelm the enemy by keeping them in their base the entire time so they simply cannot fight back.
Not to mention, both have extremely powerful defensive mechanisms: WD can prance around with his 3 regular skills, becoming a royal pain in the arse, and BLM can tank like no tomorrow with Scab Armor and out damage his enemies with Elementals until they're ripe for the plucking with Crimson Wake (Which conveniently destroys entire waves easily while the elementals provide great tanking for your creeps to survive an hour long).
PQ is probably one of the most underpowered heroes in comparison, very little lane control, excluding her ultimate, which has a decent-sized cooldown. She also may be able to shut down individual heroes, but she doesn't really offer anything in battle, so in essence she just makes it a 5v5, rather than a 6v5.
Pirate, as previously mentioned, has issues with runners and being able to actually catch opponents. Granted, it helps to have heroes like Jimmy, DotM, or etc, on your side, but other heroes that are able to produce nearly the same damage output as him have methods to help them catch up. (Jimmy has hook, Toro has a long range stomp, Pory doesn't even need to be relatively close to dish out damage due to Fireflies long range, but if they come close they're pretty much dead) In the end, Pirate doesn't need a huge buff, but he needs something on Flying Dutchmen to make the spell a little more worthwhile as it's very underwhelming.
Inquisitor, since his ultimate nerf, suffers *relatively* the same issue as PQ in that he's excellent for evening out the playing field, howvever, since his spells are a little stronger and he actually has a source of damage, he has the capability to take out heroes, and his Smite is nice for instantly removing another low-mana hero like Jimmy, Toro, etc from battle. Like Merlin said, his ultimate could use some loving to make him up to par again.
Disciple is relatively in the same boat as Pirate. He's useful, and not as useless as someone like PQ, in fact, he's downright awesome to have as an ally, but his passive pales in comparison to other skills. It's nice to have near-infinite mana, but... where exactly are you going to find time to fit it in? DotM's primary source of damage is Lunar Tides, and CtM is his most renowned skill which is useful in any situation that Palefire simply gets left behind. On top of that, DotM isn't going to be stacking attack damage, so it's a little... gimped. It doesn't make sense for DotM to build himself as a physical DPS character, and as a result the mana steal on his passive tends to be very low. In essence, it just needs to find its way to becoming a little more useful so that people would actually think about using it more frequently since right now it simply hides behind the rest of his skill set and leaves him slightly gimped compared to all the characters that are above him, tier-wise.