If you want a classic spellcasting experience, the elementalist is probably what you're looking for. Rather than dealing with illusion or the icky undead, elementalists use their magical aptitude to directly commune with the elements, unleashing powerful attacks with fire, water, air, and earth. As a result of this variety of skills, elementalists are restricted from using weapon-switching and have a very small number of weapons that they can use. However, each weapon effectively has four different skill bars available to it, ensuring that there'll be plenty of variety to work with. In addition, elementalists gain the ability to summon elementals, and can even eventually use their connection to the elements to summon powerful weapons, or even transform into a living avatar of an element.
The elementalist switches between attunements with the function keys, and can switch attunements between elements in the middle of battle, if desired. You won't begin with all of the elements unlocked, but you'll get them all soon enough. Fire skills are usually going to involve dealing lots of damage and burning conditions; air will let you control enemy movement in addition to dealing damage; water will allow you to more easily heal teammates and support them; and earth will deal damage over time and gain defensive buffs.
When you put points into Attunement Recharge Rate in your trait line, you'll be able to switch between attunements more quickly in the heat of battle.