From what i can tell, although they can shape magic in the form of skills, the people of guild wars 2 primarily channel magic through their weapons in order to shape it; thus i must question what exactly happens when they fuse the magic of the two weapons.
For my first suggestion i sound like a magician fusion auto spells and possibly one of the two offhand spells being a fusion.
Warhorns for instance could be a once every five second `very minor` aoe-heal mixed into the auto attack that effects all within hearing.
Pistols, daggers and the like would be a second shot.
Foci could be a passive damage increase or maybe a magical chakram-like attack.
Shields could be a three second absorbion shield every five seconds that can take up to a certian percentage of the users health before falling.
Fusion spells would be the fourth slot, in short dagger and warhorn would be a different spell than dagger and focus but both fourth slots would have something that adentifies with what each hand is holding.
My second suggestion… Greater spells and Attunement of the spells spirit.
Elementalists would have switch weapon again; if they can now can you please check my elementalist and possibly my engineer as well as all i have is five weapon and five skills instead of ten and five.
The staff would have attunement shut off and would give you four greater spells, one from each element, that causes bigger effects, lasts longer and does more damage/healing/or protection for a longer cooldown: say sixty-ninty seconds.
My idea for the five spells
Instead of an Auto attack; Elemental Blast: a large direct bolt of red lightning that chains to nearby enemies as small red lightning doing minor lightning damage and setting them on fire while chaining to nearby allies as small blue lightning doing a minor direct heal and absorbing one bolt of damage; unlike the auto-attack of your average first slot there would be a three-five second cooldown and, of course, you would have to hit it yourself with a final negative factor of it being obstructable by walls, trees and the like as all direct attacks are and reflectable by things like the shield effect of a engineer. Note: the absorbing effect is all but worthless against quick attacks or group attacks but is good against powerful attacks.
Fire Nova: fire wave that sets the ground it passes ablaze for ten seconds causing fire damage to those within the area of effect for however long while also setting them on fire for five seconds that can light anyone they pass near on fire as well.
Healing Clouds: creates a master cloud for ten seconds that heals all under it and grants them a mini-cloud that heals them and all allies they get near for five seconds.
Bolt Chain: a spell that attacks from above to ignore line of sight, as dragon tooth and similar spells do, issues that some have then chains outward at full power to all within
Earthen Wall: a twenty-thirty second stone wall that can be walked on, jumped on if your above ground level already and near enough, blocks direct attacks like pistol shots, does not block indirect attacks like the aoe arrow attack, has Health equal to the caster with double their armor and takes only 10% damage from aoe attacks.
(edited by Darth Corpse.7246)