In my case on a dual bow sorc I prefer acceleration over trap since you don't need to recast it nearly as often and it's refresh lines up with surge. Also aiming the lightweight trap can be a pain
I’d say lightweight trap for bow/bow. You’ll have to cast it every 7-8s, but unlike Channeled Acceleration it deals good damage. Channeled lasts 36s but uses 2 GCD’s to cast and you miss a light attack while channeling.
Depends how you use it though, if you can run into melee range every 13s then rearming is the better morph. Or if you want to lay a trap then lure an enemy into it. Lightweight is only necessary if you plan to stay at long range all the time.
I've tried both on a bow/bow warden and consider Acceleration the better option. Yes, it does not do damage but recasting lightweight every 6 seconds hurts your rotation and is very taxing on stamina. Channeled Acceleration fits perfectly between two shalks casts and can be recasted every 3rd rotation. So I would always go for Accelerate unless you want to use Rearming and stay in melee but when why go bow/bow?