karelm, Mr.Snow, thank you very much for your (additional) input!
Thank you for the hint - I will check the book. I've read Hermann Erpf: Instrumentation (Schott, 1959) and some theory books by Diether de la Motte (difficult readings for me...)
Concerning Adams: I know the "Short ride in a Fast Machine" and "Harmonielehre" and I like these pieces very much (although minimal is generally not my favourite music). Composers I love most are Bruckner, Beethoven, Simpson, Holmboe, Rautavaara, Shostakovich, Mahler (and some more). The most impressive one when it comes to large scale is Bruckner for me.
The beginning of my piece is probably the most problematic part. It is the oldest part (containing some things I probably would do in a slightly different way today) and the other movements take many of their ideas from the first one. (This shall not excuse lack of structure, of course...)
Thanks for the remark concerning foreground/background: I wanted some kind of "polyphonic sound". However, even truly polyphonic music will generally help listeners with foreground / backgrund, so I'll have to work on this.
Oh, sorry - misunderstanding: the contrast was a goal for the THIRD movement (and could maybe be better balanced). I completely agree to the point that the climax of the SECOND movement would need some motivation / preparation (I just didn't have good ideas for this...)
Since there are recurring themes (and variations), I believe, the static aspect and lack of cionsistency has probably the reasons mentioned before(mainly clear structure, as well as foreground/background)?
Again, thank you very much for taking your time to give me some feedback on my music. It is very valuable for me to have some musician's remarks and advice.
Kind regards,
Andreas