Popular weaponskills are either:
- Increase fTP with TP (in-game described as damage)
- Increase ACC with TP
- Increase chance of critical hits with TP (meaning it can crit; other WSs cannot unless forced)
Depending on the WS the initial stuff differs greatly. Pretty sure Penta/Asuran don't gain any innate ACC, while some other ACC WSs do. There's a H2H crit WS that has an innate crit of like 50%, but Raging Rush/Drakesbane? 0%, fairly sure. Full Swing goes from 1 to 3 to 5 fTP (100/200/300) and Gekko goes from 1.5625 to 1.875 to 2.50.
Then there's some static stuff like additional hits being 1.0 fTP always, offhand hits being 1.0 fTP w/ offhanded weapon DMG, single-hit WSs gaining an ACC and pDIF bonus, and for Slugwinder, the -RACC. Also, the 8 hits cap applies, making DA useless for Asuran and not-so-awesome for dualwielded Hexa.