A couple things usually happen at the end of a novel. First of all, if we're reading something traditional, the good people are rewarded for all the nice things they did, and the bad people get lumps of coal in their stockings. (You know you're reading something that's trying to buck tradition if the bad people come out on top.) Also, if the plot has had a big upheaval of some sort, the traditional ending is the place where everything gets patted down and smoothed out again. (Again, if you're seeing an ending where everything is still in disarray, the novel is trying to stick it to the Man. The traditional-novel Man.)
So with all that in mind, what do we have here? Well, we actually have a combination of both kinds of endings. On the one hand, we've got happy, happy, joy, joy: the love ending, with Esther and Woodcourt getting together and the bittersweet family unit ending of Ada, Richard Jr., and Jarndyce. We've also got the bad-guy-comeuppance: Skimpole is outed as a fraud, Tulkinghorn is killed, and Smallweed's days of blackmail are over. Next we have the fallen-woman-must-die scenario: Lady Dedlock and the big premarital-sex, out-of-wedlock-baby, suicide situation. Then we have the political-issue novel: the horrible Chancery lawsuit implodes on itself, taking all of the Jarndyce money with it. And finally, of course, we've got the awesome murder-mystery solution: it was Hortense! With the gun! In the study! And she would've gotten away with it too, if it hadn't been for that pesky Bucket and those Wards in Jarndyce kids!
So why have all of these kinds of endings? They do go together, of course, because the novel has a really tight plot that connects all these different stories in amazing ways. But also, all of these endings tell us something about the way Bleak House is built. It's a combination of stories, plots, and genres. It's a detective novel (one of the first ever!), a romance novel (kind of in the Jane Eyre, unattractive-female-lead mold), a political novel about the failed institution of Chancery Court (along the lines of political novels about factory life, like Gaskell's North and South), and a doomed-woman novel about how sex outside of marriage is the worst possible thing ever and can only lead to the woman's suicide (even if here we have a more sympathetic picture, what with Sir Dedlock's forgiveness and everything). Whew...that's quite a heap of genres!
So what's the point of lumping so many different ways of telling a story all together in one book? Shmoop will throw out one suggestion: Dickens is always really interested in the many ways the various layers of society connect, intersect, and are isolated from one another (think of the way the highest person in the novel, Lady Dedlock, interacts with the lowest, Jo). Dickens is also fascinated by systems, institutions, and bureaucracies, and the way they serve both as connections between people and also to disconnect people from one another. (On the one hand, think of the Court of Chancery, which makes Richard angry at Jarndyce. On the other, think of the police searching for Lady Dedlock by making a kind of human web around the city.)
All of these things are distinct, all have their own patterns and rhythms, but all are part of the same world. So it is with Bleak House: the novel is a multitude of people, a huge amalgam of many different kinds of stories, and so maybe it needs to accommodate a collection of genres and endings to capture all of that diversity too.