Bramble Familiar's Adventure may be costly, but it's a great -- and repeatable -- way to generate value straight from the library with three different relevant card types
Someone smarter and better paid than me can do the math for you on when to stop casting spells to increase the storm count before you cast Crackle with Power and what the trade-off of spells-to-X-value looks like
The answer is flexibility
If it happens to deal combat damage to you (usually due to a redirection effect, which would be unusual), the ability won't trigger
The Reaver Cleaver will give your Orc Army trample, and more mana in the form of Treasure tokens
I don't believe this is top tier competitive, but I think the fact that people would like Nekusar's effects to take place for a while, might lead them to underestimate it more often than not, making it stronger than he would naturally be if not for the greed of our opponents