Hi
Heres my 2 pence worth.
El Ninho did have a drastic effect on a lot of sites but there are islands that still have a lot of un-effected dive sites. The deeper mid channel Thila sites held up remarkably well because water temps at depth were just slightly cooler than shallower sites. Island fringing reefs really got creamed although there is evidence of grow back. Try to find an island that offers plenty of mid channel sites and don't give too much weight to shore diving at its expense.
April/May is monsoon changing season. You should be looking for a resort that is going to offer ingoing current diving for better visibility, easiest way to do this is to pick somewhere on an outer NW or SE corner so no matter which way the current is heading you will have options.
Fish life is out of this world.
I shall be in Dhdihdhoofinolhu (white Sands Resort) for the second half of May as I have been for the last two years. In 40 dives there I have seen 8 whalesharks, many manta, groups of pygmy devil rays, eagle rays, whitetips, big napoleons, turtles, a rare (for maldives) frogfish last year. Dhigu Thila still has table coral spanning 12ft wide under which I have found a baby shark and a stingray together. Half of Dhigu is covered in blue soft coral and half is red. Kuda Rah Thilla is another great site. It is one of only 3 marine reserves where fishing is completely banned (hook and line fishing is still permitted elsewhere). You can tell by the size and number of fish who swarm this area. The classic Maldivian huge school of lined snapper pictures will all be taken at Kuda Rah.
As you can tell I love it and wouldn't hesitate to recommend it to anyone looking for great diving, a terrific DO, comfortable accomodation and decent food in an extremely relaxed casual atmosphere at a very reasonable price.