you cant judge by goals for shit teams, because shit teams usually score most of their goals through their striker because their play is so limited. if you used that logic, we would've ended up with average players like darren bent and kevin phillips years ago.
the only way to judge players is by actually knowing their attributes, athletically, mentally and footballistically.
anyway, my litmus test for new signings is: would they have a good chance of making the premier league team of the season? if the answer is anything but yes, then pass.