Devil's advocate here... if you're in a situation where you're seriously focusing on getting TH upgrades to proc, do you REALLY want a stronger weapon? If you're truly after maximizing TH procs, what you really want is frequent weak attacks. The more times you hit the mob before it dies, the more chances you had to level up TH. So stats you'd like include Haste, DW, DA/TA/QA, Acc. AGI doesn't hurt for the subtle blow. Adding more DMG, STR/Atk, and to some extent DEX (acc is nice but maybe you don't want crits) are actually negatives for what you're trying to do!
If you're fighting something that you have limited opportunities to fight (say, a hard to obtain pop item or a ridiculously long respawn time), that might be the case. But if the only limit to farming a particular mob, even an NM, is time, then you may get better results in the long run by just killing stuff faster, rather than letting the fights drag out in the hopes of what may well be a very marginal increase in the drop rate.
In short: it's situational?