For a human archer, 0 spellweaving is where it's at.
Case in point: Lord Oaks
A spellweaver waits until the end of the fight (either letting their pet or their spells damage it) and casts word of death, usually for 450-500 damage (that's 50-70% SDI... approximately). In the entire fight, an archer with a composite bow hits with armor ignore every third shot and lightning strike during the other two hits for 170-190 damage for three times every seven hits. That means that the archer does a maximum of 570 damage in the same time that the spellweaver can cast a single word of death (about 3 seconds) and a minimum of around 215 damage.
The average damage comes out similar (the weaver comes out ahead in the last moments actually), but the archer is doing that kind of damage through the entire fight, which means that the weaver has exactly 0 chance of outdamaging an archer over time.
Now if you combined the two skills, then you do a little bit of extra damage at the end of the fight, but during the rest of the fight, your weaving skill is just sitting there unused unless you cast gift of renewal or attunement or nature's fury (which still requires 20 points to cast at 50%). The rest of the weaver spells are largely useless unless you have a lot of mana and meditation to go along with it.