Brand's buff on the PBE will make him significantly stronger
When the new rune system launched last month, Brand was expected to excel. There are a couple of Keystone runes that would seem to work well with his kit, both Summon Aery and Arcane Comet. And, thanks to Manaflow Band, he shouldn't have much of a mana problem anymore. Unfortunately, he still hasn't been performing up to par.
So, to fix this, Riot is testing out a buff for him on the PBE, to ship with Patch 8.1 next month. It will make him much stronger if it makes it through testing.
The buff in question boosts the damage of his passive, Blaze, to deal four percent of the target's max health, rather than two percent. This isn't too big of a difference on paper, as you're only looking at a 50 damage increase on a target with 2,500 health.
The thing is, though, Brand's passive doesn't have an internal cooldown. Every time the burning stops, you can just apply it again with another ability, and suddenly that 50 damage adds up quickly.
Not to mention, the more health the target has the more damage his passive will deal, so it will affect tanks even more. An extra two percent max health damage on a tank with upwards of 4,000 health goes quite a long way.
If this buff makes it through the PBE and into the live game with Patch 8.1, it will undoubtedly make him a much more attractive pick for both mid laners and supports.