Well, they did increase Heatseeker Missle's Damage and boosted the proc rate for the instant Unload refresh (name escapes me at the moment). I would say take Power Shot off your hotbar, unless someone else has had more success with it than I have. Tracer Missle becomes your spam ability to keep the debuff up, and use Heatseeker, Unload, and Rail Shot whenever they aren't on cooldown. Doing this I haven't noticed too drastic of a drop in my dps. It focuses on the high damage abilities and keeps the armor debuff up to make them that much stronger. This comes from a level 43 though, so if someone at 50 has better advice, follow it over mine.

I play an Arsenal Merc, so my opinion might be a little biased in terms of the bodyguard nerfs. But my plan is to weather the storm, maybe make some alts too at 50 now that Legacy content is out. Remember, a lot of mmo companies nerf hard at first and then balance upward. I see a lot of these nerfs being midigated in the coming patches. But I also played a shaman healer in WoW, so maybe I'm just a hopeless optomist. We'll see I guess.

I personally went Artifice / Archeology / Treasure Hunting. I don't regret it personally. That said, I'm not really a fan of the armor crafting professions. This is mostly because (from what I've seen) upgradable armor trumps armor with set stats. And upgradable is a bit more common than what I would have thought. I can't see armortech or synthweaving competing without the ability to make gear mods. I might be wrong though, it happens. I would say take whatever you enjoy. There is no wrong profession since it's your character and if you don't like it, you can ditch it and take something else. If you do decide to ditch, I'd say do it after you get a speeder. This way you can send companions on missions and ride around lower level areas gather materials yourself to level your new skill. Edited for spelling.

I think your best bet would be Bikes on demand. Save up materials and build them as people order them. You could also reduce the price by having people provide materials of their own. And if they provide all the materials, just charge a fee for the skill use. This would prevent you from having a tons of bikes in your inventory and if the shop does flop, you have all those materials to play around with. Other than the credit loss, I'd call that a win-win plan. Edit: And to answer your question, yes I would be interested in buying a custom bike if I had the cash.