The programming effort amounts to about the time it takes to remove the line that resets TP.
And about the boni to WS you get from that, how is it different from the 13 other slots you can already change freely, that sometimes provide even larger boni? Att+20? There's better for most jobs. DA+10? For some jobs there's better. Only TP+100 would be exceptional I guess (at least for the WS where TP actually matters).
Would it push dual wielding DDs? Most certainly, is that a bad thing? No, because damage was one of the things people in here always complained about as well. Only dual wielding job that can somewhat DD is NIN, and they're not great at that either. BLU? Their damage comes from magical damage. DNC? They're THF+1 in terms of damage, which is like saying 0+1.
I don't see how this affects game balance so much, and if it does, just adjust the TP Bonus +100 Magian weapons to work from main hand only, that's the only massive damage boost I can see (and not for all WS either). The largest factor for any physical Weapon Skill is base damage, and by that it would still be limited the way it is now, since only main hand base damage is used for WS calculations.





