Hi there, i did some testing in Spriter and...
I have one big suggestion so i could animate in spriter like im used to - DEFORMATION feature.
Currently spriter is kinda simple cutout animation tool, theres lots of similar softwares already, best tool on the market for this is in my opinion stickman from cutoutpro website, it has ragdoll physics and has great deformation layer, supports bones and control points to deform body parts , i made some animations for my games with it:
These are not possible to do in spriter currently because of limited deformation, currently its just linear scaling when you click on border and resize from side but would be great to actually deform the body part with bones or points so you could flex muscle , using one image of entire hand and assigning 3 bones to it so it will bend in elbow and wrist, without deformations like this cutout animation looks very stiff and i would like my cutout animations to not look like cutouts but like animations so they need to deform freely however i want whenever i want but in preplanned places so in muscle areas etc. but would be best if i would choose deform places myself.
I recommend to give stickman software a try, i can upload one of my characters for devs to test how it works, if spriter could get close then it would be really great.
You can check out more of my animations all made in stickman cutout animation software on my deviantart:
http://bwwd.deviantart.com/gallery/?offset=0
Im not really a fan of using bones all the time cause they can also limit you, sometimes character must stretch his body for dynamic effect and with bone its not possible or if stretch is too big then bones are bit misplaced, would be nice to have similar control points like in stickman, that allows for full control over single body part, you can add as many points to it as you like and then stretch them out.
This is screengrab from it:
http://i.imgur.com/NL4zgLD.jpg
I rarely use bones in my animations maybe for head so it wont deform that much, but i controll pretty much myself how far body will stretch, or maybe you could introduce bones that could stretch(stickman has them too).
Anyway its easy and fast to make character in stickman you just import body parts and click on them to create points then assign every part to points and you move points around to create keyframes, thanks to ragdoll physics animations are very fluid.
Im currently making platformer you can see some gameplay vids on deviantart profile, all chars are cutouts, everything is drawn by me .