[Sam Baughn]

How muscular you look is very dependent on body fat and the size of the muscles in your arms. Overall strength isn't. It's possible to pack quite a lot of muscle into a human body without it being super visible. Plenty of women who lift pretty impressive weights look perfectly feminine.

I wouldn't be shocked if genetic engineering could make human muscles a lot more efficient pound-for-pound. Most animals seem to do better, although there might be a trade-off with fine motor control. Also, random mutations being constantly introduced into the gene pool mean that it's possible pretty much every biological system influenced by a lot of genes is a little less than perfectly suited to it's function and genetic engineering might be able to make improvements just by counteracting the random noise.