Warlock is the real deal. He isn't niche in any regard. He's a massive problem for the opposing team no matter how you play him (unless you play him poorly!). I'd like to think that makes him superior in nearly every situation, though I know saying the word "every" and it ever being true is a fool's dream. So I'll just say most situations.
Shadow Demon is a common pick that instantly destroys Warlock's long cooldown ultimate with the click of a button from far range. Alternatively, diffusal blade carriers also wreck the only reason Warlock is picked in the first place. Also alternatively are heroes that can pick him from afar and wipe him out before he even gets to do anything, like Storm or Clock or Qop or Pudge. Warlock usually isn't afforded the luxury of a BKB or Kraken Shell so he's susceptible to being killed or forced to blow his ultimate. I don't remember the last time I lost to Warlock.
Sometimes you might value Enigma over Warlock. Enigma can free up a lane and farm the jungle. Enigma also power farms faster than many laners. Enigma can also push very early, can gank, and has a 5-second BKB-piercing AOE ultimate, whereas Warlock's ultimate pierces BKB for like, 0.5 seconds before getting blown up.
Sometimes you might value Tide over Warlock. Tide can roam and gank with just a bottle. Tide is a decent offlane. Tide is an awesome mid solo against other melees, and he doesn't really die to roaming ganks like Warlock does. Tide is guaranteed his ultimate almost every fight. Tide outputs more raw damage than Enigma or Warlock. Tide can also be played as a support with lane presence, unlike Lock. Tide killed Kunkka and his crew while Warlock is a little bitch.
Different heroes, different roles.
Would Meepo work as part of a defensive trilane? It would solve his problem of getting harassed out of lanes, his net can be used as a follow-up stun to a more reliable stun or slow, poof is a pretty decent nuke early on, and the supports could stack jungle camps for when he's 6. Net even prevents heroes from going invis, which would be nice against someone like a solo BH. Is it just a case of other carries being better at it?
That's his ideal position IMO. Why it's so ideal is not because he can get EZ kills (he can with a proper set up), it's because his supports can stack the jungle for him so he skyrockets out of control as soon as Meep hits level 7. Only do this if your opponent is doing a defensive trilane too, because Meepo is pretty weak in a tri v tri situation. If the opponent is doing a defensive trilane, you'll easily win the farm and xp war and can crush them midgame. In ideal scenarios I can get a ten-minute aghanim's scepter.
That's not how you spell Treant.
are you guys actively trolling me
Also guys my monitor looks really weird ever since I got a 3DS, are my eyeballs going to explode?