The EU gains nothing from letting Britain off easy, and has everything to lose. Making it easy for Britain to leave and maintain all their existing trade agreements with EU partner states simply emasculates the EU and everything it stands for and is trying to accomplish.

You may well be right. Ultimately it's hard to say how individual states will react. Juncker was fairly testy in calling it "not an amicable divorce", although Hollande was more positive and Merkel mainly urged caution as well as reportedly stating that relations with the UK would be "close and based on cooperation".

Personally, I think that money talks, and the EU will want to continue to have access to UK markets and vice-versa, so future agreements will have to be somewhat beneficial to both sides (although I'm sure compromises will be made on both sides, as well). There is some danger of other states wanting to leave (thus threatening the integrity of the EU) but, as I mention in another reply, referendums take time to organize, and in some ways the UK was better positioned for an exit than a lot of other members. It's difficult to say how many countries will actually even put together referendums, much less leave, but I think it's a bit premature to claim that the EU is in serious jeopardy, even if the UK's exit is smooth/beneficial.

Personally, I'm hopeful that future agreements between the UK and EU are drawn up with cool heads and based on sound economic principles, rather than being predicated on the idea of punishing the UK or on a fear of being 'emasculated'. Ultimately only time will tell, though.