I said I'd report back after testing the FD patch, so here's the info :
After 2 days of usage with the 2s FD patch the battery use is similar to the one without. As a note, the Fast Dormancy is not really a problem, i got almost 2 days of usage from one charge (i was at 15% after 42 hours of usage).
In battery stats, DataTracker-FD is at 2.7% so that it's not really using too much battery.
I didn't test the "no FD patch" since the FD doesn't seem to be the problem of high battery usage anyways.
I think there are other apps that behave badly, for example Facebook even though every update is disabled it still starts up from time to time, i had to "freeze" it for now.
What is strange, i see in the battery stats that the phone wakes up quite regularly, i tried to stop about every app that i know makes updates. Is there a way to see what app actually wakes the phone up ?