What does “able to teach mean”? Does it mean “the most able to teach”? Of course not. Paul wouldn’t have sent Timothy to Ephesus if he felt that the priority was to create eloquent speakers. Apollos or another candidate would’ve been more useful. Paul sent Timothy because Timothy was able to reproduce Paul’s kingdom teachings. Timothy wasn’t perfect and didn’t need to be, but Timothy steadily improved and was able to effectively help many. Today, should the priority be better style or more believers reproducing kingdom content?