Agreed. The various Expertise weapons skills should not be balanced solely on dps, so that they end up the same. They should offer some interesting tactical options that change playstyle...perhaps coming with synergies.
The example of adding a parry chance to Single-handed is interesting.
Synergies with other skills could also be interesting...
For example:
1) Fatality and Death blow each gain additional bonuses, based on AND while using Single-handed skill (to emphasize a style of precise stikes). As well, Ranger Stealth extends its stealth approach ability to anyone using Single-handed style, to tap into a playstyle that favors an assassin's deadly approach.
2) Defensive Posture adds an ability called Block, based on AND while using Weapon-and-Shield (to emphasize a defensive style). Effective against missile and melee weapons.
3) Battle Rage increases Regenerate based on Dual-Wield, and while using this style. (He becomes a threshing machine who laughs at blood.)
4) Whirlwind adds a small stun chance based on, and while using Two-Handed style. (Massive sweeps.)
5) Thousand Strikes adds a blind chance, based on, and while using Unarmed. (Fits the martial arts stylist.)
6) Bleed extends a percent of its ability to bow attacks, based on Ranger Strength
Other interesting possible synergies:
1) Casting Liftap with a Summoned Undead or Ghost nearby extends its duration timer. (The dead feed off the life energies being released.) Does not affect a summoned Demon.
2) Points in Fireball and Firewall each add bonus damage to one another (for the Fire Mage in us.)
3) You have a chance of gaining XP from Charm kills based on your Wisdom Skill.
4) While Way of the Wise Wizard is active, Polymorph and Charm gain a bonus to level effectiveness. Heal is cheaper to cast.
5) Master Herbalist substantially increases poison damage of Poison Arrow.
6) Curse, Blind and Fear each have a chance of overcoming spell immunities, based on Summon Mastery.
Just some ideas

Fin