Kensei's One with the Blade enhancement makes each melee focus weapon centering.
How about a multi-selector that would make each focus weapon favored. Probably no need to restrict this to melee.

Similar option could be available for Vistani's Deadly Blades. Probably no need to restrict this to melee. Make daggers and throwing daggers a favored weapon for you.

Racial enhancements: Wood Elfs have the option to make their racial weapons count as favored. Can we add similar options to few other races?
- most notably dwarves should get it, I'd suggest adding it to the t1 enhancement dwarven weapon training, given their martial and clerical traditions
- drow and gnome should probably get it later
- tiefling scoundrels - t2? maybe they cheat the deities to grant bonuses to these weapons...
- razorclaws + handwraps... why not