Cultivate wisdom or work on compassion?
I don't remember which teacher or even which tradition I've heard this from, but I definitely remember some Buddhist teacher specifically advising to focus on "that sheep that fell far behind".

This wasn't about skills per se, he didn't mean we should keep picking up skills like skydiving, motocross, crocheting etc - and other such ones that we are "bad at". Rather in context of cultivating the Buddhist path, he advised us to focus on the most glaring neuroses we have that make us less universally capable in various life situations. Like, if someone is a very adequate person but, say, has awful social phobias (among a dozen other less troublesome weaknesses) - one should focus one practice on the worst or the strongest issue. 

I guess the idea is that by focusing on biggest issue one at a time we can discover the deepest attachments/hangups and get the most benefit from uprooting them. Also, prioritizing it like this addresses the issue with bypassing or procrastinating work on one's serious obstacles to Enlightenment, while making seeming progress in less problematic areas of one's life.