I made a manual Save before accepting my Specialization, and was able to return to it when I changed my mind as a Mage. Perhaps do a look over the Passives, and see which best fits your play style as a Rogue. My next Rogue is a planned Assassin to see if it also works well for a ranged leader.
I've done an archer assassin before... In DA2. I actually preferred that assassin over my dual wield assassins I'd done previously in DA2. But archers in DAI definitely play a bit differently than in DA2, and assassin also works very differently (no awesome assassinate skill that can do 10k damage in a single hit anymore...) which means I can't really use that as any sort of indication of what DAI assassin will be like for a DAI archer.
Compare passives?
Knife in the shadows is useless like all critical chance passives, since equipment and leveling alone can get you up to 70% or 80% critical chance per hit anyway.
I was never here is... Actually pretty great.
Throatcutter looks moderately useful... Eh, maybe not. That will only add 20% extra damage when they're on their last health point, so it will only add extra damage when they're basically a hit from death anyway.
Gaps in the armor looks great too, I find my rogues have too low armor penetration as it is.
So 2 greats, 2 craps.
Set them up boosts elemental mine damage, right? If so, not bad.
And take them down looks crappy at best. A mere 5% extra chance to critical? That's like, what, 2 points in cunning's worth of critical chance? Even if it's for the whole party, 5% is so paltry that it's not even worth considering.
Tricks of the trade is useless, I don't even have any status effect skills. Unless it makes knockdown last 10% longer? No, that's too minimal to even be noticeable.
Opportunity knocks of course looks brilliant, especially when used with the looked like it hurt passive. This right here is the bread and butter of the whole specialization from what I can tell.
So one good, one amazing, 2 craps.
Not sure if either sound significantly better than the other.