So. After 1 Year with an cleaned up Stock ROM 4.0.3 i made a full Nandroid Backup via CWM and installed the Koshus 0.9.2 ROM. I must say after cleaning a bit and installing all myapps i see, that it works more stable as before.
The Sleep of Death comming only when the WLAN-Adapter is disabled in settings. With a Stock ROM i always disabled W-LAN, when i was online with WWAN-Adapter, now i don't make it anymore, and i can't say, that the battery drain faster.
The only negative thing, that i can say is: Touchscreen will be often disabled when in Sleep-Mode, it must be enabled first with the "Globe-Button"
Maybe someone knows a better way to get rid of it?
The ROM still need some Polishing, as i said, i would donate to Kushu or to somebody else, who will try to polish this ROM, make bugfixing etc.....