Is there a surge in the number of boat migrants compared to 2015?

No, the numbers are stable. There have been over 46,700 arrivals so far in 2016 according to the UN's refugee agency, compared to 47,463 in the same period last year. While the Italian navy, coast guard and EU rescue vessels intercepted an average of 15 migrant boats a day last week, there were almost 2,500 fewer arrivals in May 2016 than 12 months earlier.
Are Syrian refugees switching from the Balkans route?

Despite predictions the closure of the route from Turkey to Greece would push Syrian refugees to attempt to reach Europe via departure points in Libya and Egypt for Italy, there has been no evidence of this so far. Almost all of the migrants come from Sub-Saharan Africa.