As printed, TWF has very high opportunity cost for a fighting style common in fantasy, so many a homebrew has been suggested for it. The idea of using Snap Kick style mechanism isn't my own, but I figured I'd codify it anyway. Please point out how broken and/or sucky the following suggestion is:
And yeah, it's basically TWF, ITWF, GTWF, PTWF, OTWF, Dual Strike, Two-Weapon Pounce and Double Hit rolled into one feat (and replaces all of said feats, as well as Snap Kick).
[Edit]: Included a line about it not working with natural weapons. Sorry, totemists.