I've been looking at making a character for a 4E game; the group needs a defender. I already play a fighter in another game and I don't really want to play a paladin which leaves warden as the only choice and unfortunately the concept doesn't grab me - the game is core only so the swordmage is not an option.
The swordmage is core. Everything published by WotC is core, according to their 4E definition of the concept. Breaking away from core, you could also try the rune soldier

(see my sig)
My group:
Gnoll Rogue (striker)
Saproling [Tvari 3PP] Artificer (leader)
Catfolk [+2Str,+2Cha Longtooth Shifter] Rune Soldier [3PP] (defender)
Minotaur Barbarian (striker)
Dauthi [Shadar-Kai] Witch Doctor [3PP] (controller)
So we have 40% striker, 20% everything else.
In a previous game:
Dragonborn Fighter (defender)
Elf Monk [Ranger] / Rogue (striker)
Human Ranger (striker)
Human Wizard (controller)
50% striker, 25% defender, 25% controller
In another previous (and hopefully re-starting) game:
Warforged Cleric (leader)
Half-Elf Rogue (striker)
Half-Elf Warlock (striker)
Tiefling Ranger (striker)
NPC Human Paladin (defender)
60% striker, 20% leader, 20% defender
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