That's a cool idea you have there, you could do something like spam orders, barbs, or whatever, while your pet destroys things. Or you could always just.. use no pet, and take the lovely skill known as edge of extinction. Just look through the skill list and pick out what seems cool to you, and use it. It's hard to go wrong, really. You'll probably want at least 10 soul reaping so that you won't have much energy problems, and max beast mastery if you decide to have a pet, so it won't die. (Ranks in beast mastery give your pet armor) If you decide orders are something you'd like to do, keep in mind those are sacrifice skills, and they are being spammed. That means that you'll need to find a viable way to keep your hp up.
The only real downsides that I see are that you don't have expertise, so it might be taxing on your energy to spam pet attacks/defense skills, while using necro skills. I haven't tried playing a beast master on a non-primary ranger, so I can't tell you for sure, but this is the only problem that I can really think of with your idea. There are a lot of ways around this, most notably soul reaping. If you go the blood route, you also could go for offering of blood. I'd stay away from ferocious strike, unless you don't have energy problems, simply because you have no expertise. The gain that you get from the skill will be a lot less than a primary ranger would get.. but I guess you could always take it as a spammable, high damage attack.
No matter what you end up doing, have fun, and enjoy your character. Any more questions, and I'd be happy to answer them as well.