And there is a lot to be discovered, Johan! 
Indeed, there's a lot of music to be discovered : his catalogue counts more than 200 scores, ranging from large scale oratorios and operetta to the symphony and simple "chansons" .
I have Harry Halbreich's 1992 ( Fayard/Sacem ) excellent biography ( French only, I fear). As can be expected, success and failure were Honegger's due.
Jeanne d'Arc au bûcher and Le roi David were (and still are) hugely popular, he wrote many scores for plays and films , experimented with the "bouteillophone" ( tuned bottles ( filled with water)as used in "Le dit des jeux du monde", ondes Martenot, the Dynaphone ( another obsolete electronic instrument),the score is lost..), wrote beautiful chambermusic,ballets and some very interesting pianopieces.
I can recommend :
The early (1922) Cantique de Paques (for women's chorus & orch.) A very short ( ca 6 mins) fragment from " Mystère de Pâques" ,that never got realised. It is lovely however, influenced by Debussy, but one recognises Honegger's own style clearly ( the gorgeous Alleluia's from le Roi David!!).
Phaedre - suite d'orchestre ( with 8 alto voices). Once available on an Olympia disc ( Rozhdestvensky)
. Very mysterious and dark music . The fragments are quite long and form a satisfying whole .
Judith - a biblical oratorio. Shorter than Le roi David and Jeanne d'Arc. It derives from a "serious" opera with the same name. Quite "cinematic" ( with a reciter telling the story in short,evocative scenes) and thrilling. Two good recordings : Abravanel/Utah (1964 -) with Madeleine Milhaud as reciter - some "strange "French from the Utah chorus...), Michel Corboz/Gulbenkian on Cascavelle.
Antigone( 1924-1927 - text by Jean cocteau) : a real opera,lasting 45 mins. and possibly, with Horace victorieux, Honnegger's most expressionistic work. (It was available in a live 1960 version on the BOURG label ( Geneviève Serres, Janine Collard, Jean Giraudeau etc. The French National Orch/Maurice Le Roux)
We're very far removed from the gentle Pastorale d'été! Antigone is atonal for most of the time and quite violent. ( Think of Strauss' Electra, and, possibly, Schoenberg's Erwartung - Halbreich is not sure if Honegger knew that work).
It is a difficult work and asks for real concentration. The performance I mentioned is not perfect, but still a wonderful reminder of great style and perfect French prosody!
The Timpani label has issued all the chamberworks and some rarities (always interesting, often a bit "weird" and fragmentary)
Le dit des jeux du monde
Amphion - a melodrama for Ida Rubinstein ( of Bolero and Jeanne d'Arc fame),coupled with an orchestral suite from l'Impératrice aux rochers
Sémiramis - a ballet-pantomime ( another work for Rubinstein!) with soprano solo, 2 ondes Martenots and chorus).,coupled with several "inédits" : Fantasio, suite from La tempête, Blues from roses de métal etc.
The oratorio "Cris du monde" can be found on a Praga CD ( OOP,I suppose)( Serge Baudo with Czech forces). It is a pessimistic work that reflects both the uncertain times of its composition ( 1929!) and Honegger's own existential fears. The performance is only OK - sung in Czech, and clearly showing its age.
Michel Corboz conducts also a good performance of Cantate de Noël and La danse des morts on Erato/Cascavelle/Musiifrance (1990). Idiomatic and stylish and..OOP.
Peter