Well done for sitting through Siegfried and even watching some of it twice! Even though I like Wagner and have been to The Ring in the theatre, I found Siegfried almost unendurable in one great lump. It was a good performance, so I don't blame the musicians. But then I am a heretic in Wagnerian terms; in that I would cheerfully take scissors to a good proportion of certain operas.
One thing that drives me mad is his insistence on telling everyone the same information several times...slowly....as though the audience was thick. Ever so often, even in Meistersingers, I just ache for them to get a bloody move on.
Exceptions are Tristan and Gotterdammerung, I think I would leave them both alone. I know I am in a minority as most would rather cut themselves than one bar of his music.
Anne, As you will see, I am no expert on Wagner, but I would have said Gotterdammerung is through-written and that the concept does not prevent there being arias and so forth along the way. The idea can be seen more clearly in Verdi where he moved away from obvious boxes to contain aria, recit, duet, recit, chorus, recit etc...to eventually produce what are acknowledged to be through-written pieces, Otello and Falstaff. Each has definable structures within them, but are definitely through-written.