It depends on their role in your team. If they have low tackling it is likely they will take up more of an attacking role (or play in the wingback position) as they will be stronger in other attributes if they are rated highly. For me the most important attributes are pace, tackling, positioning, work rate, stamina, crossing. I tend to deploy them in a support role - so I allow them to get forward, thus the need for crossing, but I don't want to be exposed.