Seems fine as far as it goes. In general I dislike flat bonus weapons, they seem like an artifact of a war game. Likewise the "baseline" abilities of all magic swords (glow like a torch and such) make them far more boring then I think they need to be. When all magic swords are the same, with the same bonuses and a few minor abilities (+x vs. dragons/giants/werewolves etc) they don't seem memorable, just something to replace when the PC finds something better. It feels very bland for a MAGIC SWORD!
I want magic swords and items to live up to the wonder that they promise, and one can design unique magic weapons that aren't super powerful. I generally approach them as I would designing an NPC and then make sure they have a bonus and a penalty. For example the adventure I'm currently writing has several magical "tomb blades" in it - ancient bronze age swords that contain the soul of someone - usually a warrior or king. They all have a distinct dead and cranky person within, and require a sacrifice of blood (HP) from the wielder to resheath - while leaving them unsheathed too long lets them take over their wielder. A fairly powerful example:
Blood Drinker (1D8): A long, thin, heavily corroded bronze weapon, more point then blade, set in a horned hilt of battered gold. The style of weapon is exceptionally ancient and tomb blades of this type are sometimes called “first swords” or “mother swords” due to their great antiquity. The soul in Blood Drinker is so ancient and unstable that he no longer has a name, a sense of self, or memory of his own face—only raw and pure aggression. To draw the blade sword is to have a shaggy naked man encrusted with filth and dried blood step from a reeking cavern of slaughtered meat and viscera to crouch in one’s mind, growling.
Powers: The sword is pure violence. It screams and howls with metallic rage when unsheathed, both in the mind of the wielder and in the real. The sword pulls its wielder into attack after attack, frenzied with the need to shed and absorb blood. Attacks with the Blood Drinker that hit allow another attack (against the same target or another) until an attack misses, and may be directed at any enemy in melee or reach range (20’). Blows from Blood Drinker are always injurious, as the blade draws blood from wounds it inflicts, spraying it with abandon, and drenching its blade and wielder. Any hit with the Blood Drinker that inflicts less than 4 points of damage and doubles the amount of damage done.
Cost: To Sheath Blood Drinker requires a great deal of blood, but it need not be the wielders’. If it has not killed it will inflict 1D8 x the Wielder’s HD in damage when sheathed, but for each foe slain it reduces this amount by 1D8 (down to 0). If it is not sheathed within one round of ending a battle it will begin to scream increasingly loudly (likely to bringing others to investigate - and for it to kill), but the berserker spirit trapped within the sword will also begin driving the wielder into a frenzy. For each Turn the sword is unsheathed when not in combat the Wielder must make a 5D6 roll against Wisdom or fall into a berserker state, attacking anyone nearby until they are dead. For each person slain in this state the wielder can roll another Wisdom check at one 1D6 less then the previous check.
