@MysteriousFX Thank you for that well thought out analysis. I was tempted to buy this after it was suggested to me yesterday, but I think I'll hold off just in case my DM decided to veto it. I think a post like yours would also be really useful if you could post it as a review for the product, just so people know what they're getting into.
If you're interested in something sort of between the nightblade and the trickster without the power issues you've found with this product, you should definitely check out Ertw's Beguiler. I've just begun to build my character with it and I'm really excited to start playing.