So I'm beginning to think Silencer is anti-fun crystallized, fermented, and refined. He's balanced, but is simply the most annoying, frustrating single hero I can think of to have to play against for the majority of the game. Curse combos are just frustrating as hell.
Silencer tags you with Curse of the Silent. If you cast, you blow a lot of mana presumably without using it effectively. If you don't cast, you take some damage and lose a lot of mana.
Once Silencer gets the new Last Word, it gets worse. If you cast, you're consuming mana inefficiently and will get hit with Last Word immediately after. If you don't cast, you lose a lot of mana and some health and get hit with Last Word immediately after. Not at all overpowered, but just annoying as shit to have to deal with, complete anti-fun.
On a related note, I really don't like the design on Last Word. I really think that it should be a choice on the victim whether they want to be silenced now or be disarmed later, with the only constant being that you WILL take damage from it at some point. Right now, if you cast, you get silenced. If you don't cast, you get disarmed and then silenced anyway.
It seems like it doesn't really encourage much thought on Silencer's part or the victim's part because Last Word is always going to be good to cast on anyone and everyone, rather than trying to decide "okay should I put this on the carry to try and force them to use blink at a bad time, or do I want it on a support to prevent a spell combo?"