Mabhuh was an easily replaceable operative, while good Mossad agents takes years to train. Risking so many Mossad agents for the assassination of a nobody was a ridiculous decision. I can only attribute it to a sense of omnipotence by the recently replaced Mossad chief (Dagan) after serving too long in his post. I give myself credit for realizing this when the number of advertised agents pictures was much lower than 27.
Netanyahu condemns West Bank arson attack, calling it 'terror' (Haaretz)
from the article: Germany issues new arrest warrant for Israeli suspect in Dubai hit