I’m currently A2>QS3>SR2, going SR3, so here’s my advice.
Drop Rogue. If you want mobility, Rogue will end that for you. Unless you feel like investing upwards of 60~80mil on Werewolf cards, you will be spending far too much time trying to get behind your opponents. It’s alright for killing bosses where you have someone else to distract it for you, but in almost any other situation, it’s pretty impractical. And without the cards, you won’t get any crits from your Retreat Shots, which will severely limit your damage potential.
A2 gives you full uptime on Swift Step plus the Crit Rate attribute. This means +25% crit rate, which is a huge bonus that costs you very little. On top of that, the extra levels in multishot will be a good filler for you to use between your Running Shot cycles until you get the SR skills to fill the gap.
I don’t know how far you are into QS skills, but if I were you, I’d drop Rapid Fire for max Stone Shot. Having that ten second stun can really open a lot of opportunities for you in more difficult content. I currently have Rapid Fire 10, and I never use it. Level 1 is enough for the attribute, so I’d leave it there. I wouldn’t say its worth skill resetting for, but if you haven’t put the points in yet, consider that.
As a QS3, you don’t really have any need for Limacon. It doesn’t stack with Running Shot (Limacon buffs your C attack, RS buffs your Z attack), so as long as you have a Grand Cross/DGC (which is a lot easier to obtain now) you won’t really have much need for Limacon. Sure, it can hit multiple targets, but if you want to hit multiple targets, you might as well just use a skill.
Otherwise, I’d just make sure you get Concentrated Fire maxed as soon as possible. I’ve been leveling it first (even ahead of Retreat Shot, sacrilege I know), and it has been fantastic.
As far as stats, its pretty much what pereyraibz said. If you have the money, get STR. If not, get DEX. Personally I ran a 3:2:1 STR:DEX:CON, and then stopped investing in STR at around 120 points in and CON around 50 points in. This gives me a nice healthy crit rate with gems, and I still feel good about my damage. For cards, I would recommend Ellaganos if you drop Rogue, otherwise definitely Werewolf. Glass Mole is another option, but imo its overshadowed by the other two atm.
If you stick with Rogue, you need a LOT less DEX. You could probably do something like 40~60 points in CON, 30~40 points in DEX (for some basic hit rate? not really necessary if you keep your gloves current) and then the rest in STR. Again, I don’t recommend this path, but its certainly viable.
For equipment, all you really need is Grand Cross til 220 (up to +10~ if you can). The first big item you probably want to drop money on is a Manamana at 170, followed by a Didel Grand Cross at 220. I’ve found just whatever white/blue 2h bows I come across are sufficient for dealing with flying enemies, so I wouldn’t worry too much about investing heavily in a 2h bow.
I personally like Green Gems for my weapons, but with the new gem changes, reds are a lot more viable. You can season to taste, but I’d recommend greens until you are carded/wearing Sissels, then switch over to reds as necessary.
Personally, I have gotten a lot of mileage out of my Vubbe Fighter Gloves on my SR. With those plus Manamana, you can hit up to 2 Mediums at a time with your skills, which adds a lot of power (considering how plentiful medium enemies are) for Multishot and Concentrated Fire. No bonus to Running Shot or Retreat Shot though, so not necessary by any means.
For attributes, there aren’t a lot of important ones for QSSR. Naturally, you want 1h+2h bow masteries maxed asap. If you get A2, the Swift Step Crit attribute is absolutely necessary. You can grab the Crit Def Reduction on Rapid Fire for a little boost to your crit rate, and then after that it’s just putting damage into Concentrated Fire/Retreat Shot/Assault Fire.