Hmmm, on the subject of poorly written... Unlike the crab which was poorly designed/thought out, or the invisible blade, which was poorly split from the Master Thrower, I'd call out the errata for the naztharune rakshasa. While better than the base (which meant that naztharune would only have 1d6 sneak attack until they took levels of rogue) it was instead changed to them getting the sneak attack of a rogue of their total hit dice.

So, class levels taken afterwards will continue to grant sneak attack. Go rogue/assassin and gain double the sneak attack progression! Or, better yet, Daring Outlaw Swashbuckler for, yet again, double sneak attack progression.

Still one of my favorite monsters though, that and the marrulurk. Definately want to play a rogue using one of those some day.