Trying to make a completely DEX based character. (Bard, if it matters.)
Finesse allows DEX to attack rolls with light weapons, certain other weapons, notably the rapier and whip.
Slashing Grace allows DEX to damage with light weapons, and one handed slashing weapons. Could take Fencing Grace for Rapier, but...
Piranha Strike is basically Power Attack for light weapons. (Not rapiers or whips.)
So really to get the most out of these feats is to use a light, slashing weapon? (in the case of the bard, a dagger or a sickle.)
IS this correct? No other way around it?
Seems like it.
Some archetypes will give more options, but for the baseline bard that's it.
Then there's proficiencies gained from races, traits and others, of course.
Also, Effortless Lace might help, as a workaround.
Could always try to find a way to get your bard proficient with a kukri...
for free dex to damage class(with scimitar mostly,but not only) look up the whirling dervish swashbuckler archtype(get it all by level 4).
It's common practice for Dex builds to have at least a 13 str so they can pick up power attack. It lets you pick up some of the stronger weapons and still get extra damage.
Instead of going for piranha strike/power attack, you could always go for arcane strike.
Slightly less damage, but It won't impact your to-hit. It is usually just as effective DPR wise for a 3/4 BAB with full caster levels.
Wakizashis are the best light weapon in the game for crit-fishers (unless you also need to throw said-same, in which case you settle for ordinary daggers).
Normally you'd buy an opalescent white pyramid ioun stone for martial proficiency...but that doesn't help bards, who lack martial proficiencies.
-- All the more reason I'd don't mind tossing a multiclass dip at bards. Swashbuckler or paladin, for instance, dovetail nicely.
1. (Any martial class, with a preference toward either urban-rager, or Yojimbo samurai.)
2. (rest Bard, unless 1. Paladin, then you'll pick up one more level of that.)