The main idea is to abuse the defenses to stay alive, while not letting up the attacks with the sword until they're dead.
- As mentioned already, there are plenty of ways to make attacks unavoidable, from using attacks like Flameblast or Surging Wave to enchanting a creature with Falcon Precision.
A defense helps, sure, but you shouldn't rely on it too much. I've played enough Forcemaster to realize that.
- You may have plenty of defenses in your book but you still can use
only 1 defense during the "avoid attack" step of an attack.
If that defense "misses", the attack goes through and all other defenses you may have on you do "nada".
- If your opponent plays only one or just a few creatures, a rather common occurrence, it may turn out he makes only two/three attacks per round. That means you may have far too many defenses in your book who are basically all "dead weight" aka wasted SBP's.
- The goal of the game is still to win it by killing the enemy mage and, as useful as they may be, defenses still do not inflict damage on the opposing mage so I am very sceptical about the winning chances of a strategy that focuses on "abusing Defenses".
- The major weakness of the book however is that your whole strategy hinges on the presence of just 1 card : Sectarus.
All it takes is one Dissolve ( just ONE card, imagine that ) and your whole strategy is finished.
There is no ( competitive ) spellbook that doesn't run at least one of those and that sword WILL be targeted at least once, you can count on that.
You have no back-up swords and no Nullify or Armor Ward to somehow help prevent that destruction.
Do you really expect your opponent to leave your Sectarus untouched all game ?