I have no problems with focus groups, just that I don't think the answer to a focus group is to do exactly what they say, but rather try to find the root of what they're really saying is wrong.
Like, for example, if people complain a shotgun is bad, the answer isn't necessarily just to make the weapon more strong, but to make the level in which you have a shotgun more conducive to how shotguns work.
If there were complaints that Overstrike felt like it was for children, I would propose the solution was not to make it really hard to distinguish from other games visually, but rather to try and modify it into a unique artistic style that retained their goal of looking cartoonish without eliciting this response.
That way, they retain a unique direction, but don't risk having a toxic reaction if they've already received approval from customers.