southern europe will definitely be in the throws of spring, plenty of sunny days in spain, italy and southern france, it will still be crap in the UK, showers and clouds, and the nights will still be cold.
you get the benefit of not having to queue to get into the major sites and not paying ridiculously high accommodation charges. Easter is busy, plenty of
going on, particularly in the catholic countries. there are backpackers still travelling but not in huge numbers, you will still get to meet people and probably more than likely they will be European backpackers. it will be colder in places like switzerland, germany and Poland, my friends in austria had snow and were skiing up until only 5 weeks ago. but these places are drawcards in themselves during this time.
interlaken, salzburg, berlin, paris rocks in the spring, venice without the humidity, florence without the crushing crowds, barcelona anytime of the year is popular. london will still be good for nightlife and seeing the important stuff, its all indoors anyway. you will still meet plenty of people to share a few