Warlock gets pretty funny once you have Refresher. Multiple casts of Fatal Bonds stack, so you can 40% damage sharing on linked targets, which can lead to some pretty hilarious results if you have a teammate with a major AOE nuke. Zeus, Sand King, Qop, Lesh, etc.
The golems are actually phenomenal at pushing if you have Agh's as well since their auras stack (four golems together is equal to 200 DPS to everything in a 250 radius), but there's no way you'd have Refresher+Agh's unless that game was won, anyway.
I think Warlock would be a lot better if his golems lasted longer and/or were just better. They're worth a whopping 200 gold at level 16 (or 100 apiece if you have Agh's), and 360 move speed just ain't enough to catch heroes at that stage of the game... nor are 320 or 340 enough at the level 6 and level 11 stages of the game. They can do some impressive damage if they can get next to something and stay next to it, but that doesn't really happen much, and with a nearly 3 minute cooldown on the ulti, the golems don't last very long in comparison.