I've played a lot of Isengard Orcs, but never pure discarding. I always felt like you wouldn't be using Isengard Orcs full potential. But I'll give it a try. I never got Hollowing if Isengard to work, so I'd take them out. Add a 4th Servants of Isengard. Isengard orcs are cheap, and with that little bit of swarm feeling that you're after, you will almost be guaranteed a +3 strength.
Isengard Mechanics is good, but costs a lot. Considered taking a copy or two out and replacing it with
Shotgun Enquea? You'll never have any problems cycling with Isengard orcs, so consider adding another minion or two. (I'm almost always through the deck by site 7-8). If you want, I can post my own Isengard Orc Shadow?