If there's no limit, you can do trivial DDOS to block ANY decision of EU by corrupting one unelected person, that can only be fired by firing the whole European Commision.

That's begging for decision paralysis. The same problem liberum veto had ( http://en.wikipedia.org/wiki/Liberum_veto ).

I think it's safe to assume when we voted againist sth once, we can ignore it for next 5 or 10 years.

"re-tabling it before the European Parliament until it passes" is completely different from "tabling it again after x years after new information surfaced".

The former suggests pretty much immediate, repetitive, DoS style re-tabling and an intention to force something through despite that matter having been voted AGAINST - the later suggest good democratic processes.