Theres no denying that Brainstorm is a powerful card, and it could well give your deck a major boost if its in color
And, without some substitutions, the starter deck can't stand alone against competitive custom decks either
Honestly, regardless of circumstance, slamming this black creature on the table is probably a good idea
Aettir and Priwen would be the only other equipment I would target at this CMC
Sapphire Sapphire Ink cards are all about strategy, the playstyle may require a little bit more planning and preparation as a whole deck to get the upper hand, they are not going to be the strongest in terms of stats but well experienced players will find them the most fun to execute against others
(It's not a creature.) Enduring Innocence's second ability checks the power of the other creatures only at the moment they enter