The good points for a merger with Monarch or Silverjet is that it won't cost them lots of money in business trips... With the possible merge of Clickair & Vueling (which offices are distant for around 100 m), and EZY with MON or Silverjet (which offices are distant of around 20 m), it looks like in a low cost environment, the merge doesn't depend on network complementarity or potential economies of scale, but only of savings they could do on meeting transportation costs! :-)
More seriously, a merge with one of these airlines will give EZY the opportunity to set up a long haul LCC, so to take an advance on Ryanair, whereas currently EZY is rather late on the project.
That would be very well done!