Btw, would it be realistic to think that these attacks could also exist because people want miners to go offline in order to drastically decrease the difficulty for a week?
I don't think that DDoS can decrease next difficulty at all.
Even in cause of powerful attack most users will just switch to another pool. The total network hashrate is not affected.
On the day of the last difficulty change, all of the pools got hit very hard. The day before our network total hashrate was 14Thash/sec.... When we approached the re-target they started attacking ALL major pools, and effectively dropped the network hashrate to under 9Thash/sec.
The estimated difficulty was to be around 1.59M and we ended up with 1.56M
It is hard to say for sure how much these attacks effected the retarget, but i think they did somewhat.
For a time I couldn't connect to ANY pool. I have accounts here, with btcguild, slush, reddit, etc. They all took a beating the other day.