All the factors you mentioned contribute to the smothness of the draw. The riser length in proportion to the total length is a factor in that a long riser and short limbs will cause the bow to stack quickly and abruptly. Longbows are always going to draw more smoothly as they usually (ideally) gain about 1# 1 1/2# per inch of draw. Recurves usually (ideally) gain more than 2# per inch drawn, until the tips "unroll" and then for that inch or two it'll gain a little less per inch than it did reaching that point.
The limb design has the biggest effect. With a longbow I found the bows that have limbs that taper in the width along the whole limb have a smoother draw. I haven't noticed it as much with the recurves I build since I always use tapered laminations in my recurves. With recurves it's the length of the working part of the limb that makes it smooth, the longer the better, but too long can zap speed.
Wood type in the limbs doesn't have as much impact on how the bow feels with the exception of bamboo. To me bamboo feels more steady consistant and solid as I draw the bow. I can tell a bow with bamboo in the core when I draw it.