Let me try to suggest why the Savoy Operas are a Good Thing, the Case For.

None of them has a plot derived or adapted from any works by a previous writer.  Gilbert's fascination with paradox, his topsy-turveydom, not only played with social or political issues, but with literary conventions.  To take a blatant example, in his two earliest successes the female chorus are respectively the sisters, cousins and aunts and the daughters of George Grossmith. 

Gilbert sets up a unique dramatic set up, love it or loath it, and Sullivan responds with charm, wit.

Gilbert subverts the conventions of romantic love which are a basis of romantic operas, so, unconventionally ,tenor/soprano duets are relatively rare.  There is hardly any sentimentality in the texts, which means when Sullivan writes beautiful music, it does not seem out of place in a comic work.  I hear the soft note is slightly funny in context rather than syrupy.  One of the most lovely songs Sullivan wrote for soprano, (with Mozartian wind writing?) has as its cue the words (quote from memory) "I often wonder in my artless Japanese way why it is I am so much more attractive than everyone else.  Can this be vanity?  No, Nature glories in her beauty.  I am a child of Nature, and I take after my mother.  The sun whose rays..."

Gilbert wrote for a large team of seven regulars, but he never wrote stereotypes.  There may be no psychological insight in the way these puppets act, but they are often strongly characterised, at least in their solos.  (See my comments above about the Grossmith parts.)

It is a mistake to judge the works just by the Hits from Gilbert and Sullivan.  There is a surreal dramatic sense to the works, which is often conveyed through prolonged dramatic action set to music, notably the Act 1 Finales, but Act 2 of Pirates, much of Act 1 of Iolanthe, and the whole opening scene of The Gondoliers are continuous music.  This is a delight to rediscover, provided of course you are not put off by the elements I reluctantly indicated earlier.

Aren't they his Wards, though, rather than his daughters?  As usual, just when I want to check in my Vocal Score it's at the other end of Europe    I think he's their "father" in a legal, rather than biological sense?   I always believed this was a kind of send-up of "carrot-crunching Cornwall" - he's the only "gentleman" in the district who might meet the requirements for taking such wards under his protective wing?

Nothing would surprise me about peers, including playing truant.  I don't believe any minimum quota of attendance in His Lordship's House is mandatory for them - even now

Aha!   

And not only Gilbert's. All comedy (except for slapstick) has to be played "in earnest" - the humour arises from the situation, and not from any kind of mugging or gagging from the performers.  The Commedia dell'Arte players knew this rule of old,  and observed it scrupulously.  Although Gilbert didn't borrow Commedia plots, he realised the value of the "stock characters",  and employed them to good purpose. Nanki-Poo is a modified version of Pierrot, and most of Grossmith's roles are an expansion of Pantalone (unsatisfied virility, a grumpy nature, a miserly attitude arising from straitened circumstances, hints of a disreputable past, etc).  Almost all the sopranos are Columbina in some way or other

Well, I was sure I wasn't going potty...   the girls in Pirates are Wards!

MABEL:
Hold, Monsters!
Ere your pirate caravanserai proceeds against our wills to wed us all,
Just bear in mind that we are all Wards in Chancery and father is a Major General



Now, on the topic of Gilbert not using pre-existing stories, this is true, BUT he does spoof pre-existing stories.  Who's going to be the first to tell us which other opera has:

• two rival "crews"
• a "hero" who's washed-up on a beach
• a hero who is cursed to live for a very long time
• a hero who needs the pure love of a girl to redeem him from his piratical seafaring wanderings?

And which opera ends with the revelation that the tenor and baritone were brothers mixed-up by the midwife?

I like the double choruses too, especially when it's a slow tune put together with a fast one. There is even one in his opera Ivanhoe. In the original overture to Ruddigore, the double chorus Welcome Gentry is used, the only time that happens in an overture I think. But this surely spoils the surprise for later on, which is one of the chief attractions of the device.

A parent can indeed make his biological children wards of chancery, although it is unusual. It's all to do with safeguarding inheritance rights.

The music in Pirates is regarded by many as coming closest to grand opera. There is the famous story of how the musicians in America wanted extra pay for the premiere of Pirates over there because they thought the music was a cut above the standard music hall fare. But that was largely because Sullivan had been built up as a very important composer before he came to conduct them.

And muddled up babies? Not in the sense of the baby in Utopia Ltd, I presume:

Awful silence, no reply,
Puzzled baby wonders why.

As for double choruses, I think Sullivan claimed to have invented the idea. The first example is in Pinafore, although there is much the same thing sung by two pairs of singers in The Zoo (1875) which he wrote with "Bolton Rowe".