Old events vs. New events

[rakshas]

So I've been farming Usopp's golden pound again (last time I wasn't able to get a single skill up) and after  25+ runs I haven't received a single drop from elite.  I had farmed Alvida again as well with much better success, however, now I'm wondering if it's even worth the sacrifice of exp and drops when I could be running Kraken on expert for MUCH better drop rates on turtles, skill books, and especially EXP.  I feel like I'm dead in the water atm farming these older skill books (however valuable).  So the question is, should I even be farming Kuro elite atm, when I may not even get a single skill up for Usopp?  And that question expands to other older event releases as well, since their exp and drops rates are utter trash compared to the new ones.  The only reason I'm not going mad from raging is because I luckily pulled a Hancock from this sugofest -_-.