On the subject of "pure Spellcasters being weak" in WotR, watching Nenio walk into a room at the end of chapter 4 and let off her first Weird and watching half that room up and die is something no Martial will ever achieve. You can make it even more so if you go Demon path Phantasmal Mage since you can cast Mind Fog as a Swift Action wit Sorcerous Reflex, cast a Persistent Weird, with Demon's additional DC boosts, as a Move action, then cast another Persistent Weird as your Action. Nothing that isn't a boss survives that on Core - almost ever encounter can be ended in 1 round.
Before you get to the amazing stuff though, spellcasters are still good shit, no martial can drop and entire room into a Pit of Acid to be dissolved at your leisure. It's not 2e since the biggest change with 3e was stripping back the spellcasters ability to become immune to all damage. Instead they became masters of Save or Die. Direct damage can still be effective but its all the other stuff that make them so powerful.
