Force of Will's mana value is always 5, no matter what you paid to cast it
Simply put, it's the most efficient solution to deal with that particular color
I'm a decent Magic player and I can build a pretty good Commander deck but I'm also well aware that I've got my own blind spots and deck-building foibles that affect how I play the game
I'll walk through some of them to demonstrate: Card Drawing: As I said above, blue is #1 and black is tied for #2
I also like this as a free sacrifice outlet in Commander decks that need one, since you can equip the Bloodghast and then unequip it to kill it, but a simpler way to do that is with the Hauberk which can sacrifice anything to give +4/+2 to a dork you control, like your Commander
Mana Ramp This deck is mana-hungry, so mana ramp is incredibly important