As it stands there are just too many counters to a drain. Energy gen, GoMGS, AS and DM. The only ones that should be a true counter to it are energy gen, as it's a module, and DM.
What I feel should happen is that if you get hit by a drain, you can not get energy while you have the debuff, unless it's from DM or energy gen module.
As it stands thanks to skills like AS and GoMGS, ships can survive things they really should not beable to servive. a drain should be a death scentance for a ship. As to deliver one out side of a purge, it has to be done at close to point blank range. But you can get there hit your target with a drain, and watch them start to get there energy right back as soon as it hits, thanks to OB's such as AS and GoMGS. GoMGS is not as bad as AS imo, as you have to position your ship for it to work, where as AS is just from healing, any kind of healing. and makes a drain useless on them, even a purge will not affect OB's, so even if you get a hit with it, it's not going to be a garentied kill that it should be. Because they'll have there shields back up quicker than it will take anny offencive modules to reach them.
This is something I have seen happening for months, and it's now got to a point where OB's win battles. you could take the same ships with the same load outs and the ones with the OB's will win out over anything else.
Personally i'd remove OB's from the game. The allow you to do things you would normally beable to do in a ship, some people might think thats a good thing, as it keep the game play fresh. But I feel it's takes the true skill away from the game. When an OB saves a player from death, becuase they have it and you don't it dose not make that player more skilled, or better, it just means they a paid, or played more than you.