After doing some testing my self this is what I came up with.
Early on my win rate was…unimpressive to say the least. Given some of that was due to misplays due to a combination of playing late and having no experience with brome, and there was a lot of bad luck. I still think brome is much stronger then people give him credit for, as he has some really strong tools to compliment his bbs. I plan to do some more testing.
So lets talk about why I changed what I did. I decided to cut Dioltas because without argeons BBs I just did not like the tombstone, cutting him made room for some powerful late game tech in Magesworn and EMP, both of which are great bond targets. With the copy of EMP in there I moved one of the sunblooms onto Ironcliffe heart because man that card is good for this deck. I figured the deck had enough provoke and I really wanted to add some reach so I opted for Solpiercer over good old knight. Pierce is a really great zeal minion perfect for afterblaze, aegis, and even divine bond sometimes.
My latest change, which I am still not sure about, is adding Arclyte Regalia. Its a powerful card that helps with survive-ability which made me comfortable moving Scintilla to two, without it I would want Scintilla three. Tiger is what got cut, without Argeons BBs and not wanting to spend your other buffs on him, plus the added reach of Sol Peircer I felt he was under performing.
Cutting tiger was a mistake and regalia has been underperforming in this artifact unfriendly meta. Scintilla to 3, tiger to 2, and regalia out. Out of my many losses with the deck…almost all of them have been in tiger lethal range to.
Between getting better with the deck and my many small changes its starting to perform really well.
So take that with a grain of salt because as I said my winrate has been underwhelming, meanwhile you have done exceptionally well so the style of your deck certainly works, mine is just a different angle. As for some of your questions, I absolutely would not swap out wisp and drop scintilla, you really need wisp to keep your curve healthy and its a great heart target, and you really need scintilla for survive-ability.