I think the shortcoming to eGrissel is how expensive she is to run fury wise. If she tries to cast both spells and shoot all three shots, that's 7 of her 6 fury before she boosts anything. Technically you could say the same of any caster, but against any non pathfinder army she's going to want to use everything almost every turn, since it's just all so full of awesome. In essence: her drawback is she's actually too awesome for her fury score. She looks fun to play (and plays one of my assassination tactics of shoot knockdown gun at a caster, burrower dogpile better than Grim in some cases: inspiration lets the poor burrowers ignore those nasty abomination casters), and definitely isn't the worst. She just isn't as solid as the top tier. (This all might just be pointless blathering. I still need to find a copy to try).

Her tier also looks fun and "relatively" easy to build. Horthol, Sons of Bragg, optional battle engine, and 3 beasts might not be the cheapest, but they're all fun stuff and easier to justify than a second copy of a unit like most tier lists.

Oh, and she definitely isn't as bad as say...the skinner is?