I don't agree with you in this case. I think fast learner always has the advantages over slow learners. I feel that fast learners means they can do the same task faster than slow learners and it saves time. In the case of other things you mentioned depends on the understanding power. Suppose one slow learner took 30 minutes to understand a thing and a fast learner understood it in 10 minutes. So, is that case I don't think slow learners have any favorable condition. Fast learners don't focus on only a single matter. If there are loopholes, then I don't think that person needs to learn more and can't be considered as fast learner.