I'm nearly done with Sword of Seals (First playthrough), so I suppose I can have some sort of input on my opinion about her now that I've seen a lot of units in action.
55% HP growth isn't that bad, though it could be better. It's just decent. Same goes for strength. If the RNG is good to her, her strength shouldn't even matter with all that skill (Which is one of the most essential stats in this game in particular) and speed especially. Really dodgy as well. But as a result, she's fragile as paper. 10% Defense and 15% Resistance growths are the toughest to grow out of (Unless you were blessed like I was)...and dear god...I don't want to imagine how much damage she'll take from horse-killing weapons. Most likely instant death if they can take out several other mounts in 1-2 whacks. But she can benefit from a Dracoshield, being one of the main candidates who desperately need them.
While I'm not too big on mounts, being a casual player, it's a large boon for her. It's helps out several times and gives Sue a better chance at actually staying good and constantly gaining levels to hopefully improve some of her weak areas before you get your first bolt. I also don't really care about the bow-lock (And swords upon promotion) as penalties to hurt her usefulness, as there is always a way around something if you use it more strategically.
Sue gets a 6.5 for me, but I'll up it to 7.5/10 for personal bias.