Brann and Flurgl have to be at least tier B. Their numbers are dragged down by people being too greedy in the early game and not just going with whatever comp they can get until tier 5. But if you get there with a decent amount of health then you can virtually guarantee a first place finish because they snowball murlocs better than any other hero.
With Brann I find it hard to fit a hero power in the early game. You're usually taking damage against strong early game heroes. Murlocs are the best strategy with Brann (if you want 1st) and you usually need a turn where you level to 5 knowing you are going to take some damage. I find this a lot harder to do if you take a lot in the early game. However, I haven't tried Brann with a menagerie build yet. He may perform better in that way.
Deryl is definitely Tier A. If you see a Bronze, Deflecto, or Hydra before turn 8 (very likely) you instantly get top 4 and a fantastic shot at first.
Pyramid, Jaraxxus, and Patches are all tier B IMHO. They both do a great job of building a strong early & midgame that lets you take the time for the best winning strat (aka cheesing out poison/divine shield murlocs on turn 10). They'd be Tier C without Murlocs, though.
I tend to agree that Brann is weak. There are a lot of shitty battlecry heroes and you give up a roll for better minions to roll for them. "Get Kalycegos" is not a consistent or good strat. I feel like Tess is probably Tier B or C but haven't played her enough.
Hooktusk is a dead hero now.
I also feel like Eudora almost deserves her own "Super Saiyan" tier. That hero is bonkers and works with every strat & every lobby.
TBH I didn't know where to rank Finley so I dropped him in the middle :)
A reasonable way to treat Finley is by looking at the order statistics. If we're looking at random numbers between 0 to 1, and we take three samples from that uniform distribution, our mean value for the highest of the 3 results will be 0.75. The distributions will be different, since we'd be sampling without replacement, which is more complicated, but it's probably close enough.
As such, sticking Finley at 75% of the way through the tier list is going to be pretty fair. Out of 44 heroes, he should probably be around 12th.