With Templar what I was saying is that if you add target explodes on kill for 100% weapon damage all that massive damage you do with wambo combo to stunnable targets transfers to non stunnable targets when the enemies youbkilled with the combo die. They just have to be in radius of explosion. It can get pretty insane.
The damage can indeed reach high amounts - the problem is balancing defensive and offensive stats when you solo, in particular when you solo content that melee characters have a hard time soloing. If you're not using a two-hander, your overall damage tanks due to not being able to use short cooldown high damage skills (because 8 slots), and your wombo combo ends up doing a mere 4k damage a pop, which even doubled is mostly irrelevant when trash monsters have over 60k hp. On the other hand, if you're using a two hander, your armor tanks by 64 pre-buff, and ~90 post-horn of valor, which puts you over the edge: whenever your War Cry buff expires, Bolters will one-shot you, tendrils will one-shot you, Ogre Punches will one-shot you. As a result, you're losing the opportunity to use a second masterwork due to being forced to use a 10% armor on your chestplate.
On the other hand if you're going for a shield, you will be slightly over-armored, which lets you use three offensive masterworks, in particular Chance on hit to cast Mind Blast, which is pretty much equivalent to the templar wombo combo, except it doesn't cost stamina, has no cooldown, and doesn't require any skill point investment, just a moderate amount of stagger on being hit. Which you should use anyway, as it's how Sword and Shield maximizes their damage.
Templars are in a strange position indeed, but the wombo combo explode trick is mostly only great for damage in a party (even a party of two) where they can share the incoming load with others. The difference with other specializations is, Reavers can actually equip a sword and shield and still do good damage against those few specific enemies. Champions simply don't need a shield.