LOL right, which is why you avoid using the crappy mail system they used before and just use the Diologue system they already have to help facilitate it. 
There's still the whole "why can't I have my LI HERE" complaint, which the dialogue does't get around. I'm not saying it's a bad idea. I'm just saying it's going to be major sore spot with any number of fans who are REALLY attached to their LI. And honestly, each LI would have a good reason to be there since they're all pretty much invested in stopping Solas, seeing as how he played them.
A new protagnist gets around that and it gets around potential "Moonlighting" syndrome, where you finally get the couple together and then the plot just dies.
As for the arm thing ... with the setting the way it is, just because it doesn't exist yet, there are plenty of things that allow for its creation. vbibbi saw my big ramble as to how the darned thing "should" function in a game-play sense
, but as for what it actually is I find it hard to believe that the Inquisitor with all their resources and access to people couldn't create some sort of functional prototype by combining enchantment, magic and mechanics (heck, Bianca's mechanical expertise with Dagna's Anarchist skills would go a long way). It doesn't need to be perfect (in fact I'd prefer it be dysfunctional and painful to use to begin) it just needs to work. As for basing it off Golems ... you are right, that is a very, very, dumb idea. 
My preferred thoughts is that it not be Iron Man, FMA Automail, Highly Magical or even Made of Stone ... but something closer to a prototype "Furiosa" might be possible and it does need to have in-combat (and out-of-combat) side effects.
I wasn't thinking basing off golems as much as right now Golems are the only example we have of being able to make stone and metal live.
One of my favorite novel series is a hard sf military thing. The main character is inspired by Horatio Hornblower, who in turn was inspired by Horatio Nelson. Now the short version is she looses her arm from just below the elbow, much like Nelson did, but being 2000 years in the future they have advanced cybernetics. The problem is no matter how good a cybernetic arm is, it just doesn't replace the real thing. Doesn't have the sensitivity or the response time of a natural limb etc.
And yes, I know we've got magic, but we haven't really seen anything indicating that magic could pull off such a feat. And while I know that Dagna could probably come up with such a thing, unless we're talking about another five or ten year leap, I'd feel it's really a cheap way to get the IQ back.
I'm probably one of the few people in the universe who hasn't seen Mad Max so I'm not sure about the reference except that it is about Charlize Theron's character.
Honestly I'm both playing devil's advocate and voicing a bit of my own preference. If they were to give the IQ a new limb, I don't think they could do it justice in the most important way: how the loss affected the character. I think going through that journey would be amazing, but I don't see how it would be possible in an rpg like DA. I suppose if they were to do something like a Telltale prelude with the IQ dealing with it, it might work, but I have no idea how they could manage that AND do the base game.
Now, if they'd get the IQ a new arm just in time to get the band back together for DA's finale... That would be something.