Here's what's wrong with Brand
I've been a fan of Brand for a while and as much as people like to say he's pretty good, he's really not. He has some crippling problems which is why he does not see serious play.
Waveclear.
Brand doesn't have a lot of tools. He has damage and a very conditional stun. He has no mobility or utility. By all rights he should have godlike waveclear. Last time I played him I was constantly pushed to my turret by an Orianna, a champion overloaded with utility.
In order to optimize his waveclear, he has to Q a minion, then E, then W. So he has to use too much mana and put everything on cooldown. It's not a very viable strategy because it leaves him no way to trade with his lane opponent and they will capitalize on that. EDIT: So to be clear I don't actually do this.
His ult.
There are two problems with the ult. The first problem is it's very common that it will just fizzle and do nothing because if any target it's bouncing to becomes invulnerable or has a spell shield, the whole ult is gone. This isn't a good way to do counterplay because it's too binary and Brand has no control over it. He can choose the best target to ult and somebody else will pop their hourglass and that's it, his ult is over and did basically nothing.
The second problem is the cooldown is much too long for what it does. It's highly conditional, so it doesn't have the problem Darius' ult had where you'd just go up and do your combo on your lane opponent every time you saw them. For Brand to solo somebody it's ridiculous. He has to land his passive on all the minions to ensure his ult will bounce back to the enemy champion. He should have more chances to attempt this. He should just have more chances to attempt his ult in general because of how poor the damage can be.