The Grelod bit is a bit of genius. Lets non-evil characters find the DB too.
But in Oblivion, if you do the grand champion's quest in the arena and he lets you kill him, wouldn't it count as a mercy killing, or assissted suicide?

I personally prefer the Oblivion Db, as I always felt close to them (but I hated being a non-shadowscale argonian in the same sanctuary as Ocheeva and her bro

) and I loved 'Whodunnit?', but I have to admit, Cicero is epic, and so is being able to kill the emperor. Doesnt stop me missing Lucien, and my brothers and sister's pvssyr ("So how did the birthday contract go, brother?"). So BY SITHIS, don't let this cause another purification.