Just got back from Bunaken and Lembeh. I would do both. Spend more time in Lembeh though. Lembeh has wide angle ops, but few do them due to the great macro. If I spent more time there I would have done a couple of wide angle dives and some close-up wide angle.
Bunaken has wide angle opportunities. It rained every day...some where else.
I did 3 days of diving in Bunaken. No Rain. Rained in Manado every day. Sunny where I was.
I did 3 days of diving in Lembeh. Rained 1 day during lunch. Rained hard. After that it was a very light sprinkle. Other days sunny.
1 huge advantage of rainy season is VERY VERY few divers. Bunaken was 2 divers at the resort. Lembeh had 3. Lembeh had 3 dive guides for 3 divers. Dive guides fanned out finding critters and I could not even come close to catching up to them with my photos. I averaged about 200 shots per dive. Had major battery problems taking that many shots!
I was VERY happy with my off season/raining season time at both. I would do it again.
Bunaken has 2 huge turtles that allow you to get within 12 inches. Also some large schools of fish.
Another location for wide angle photos is Dominica in the Caribbean. Use Nature Island Dive. Small groups, small dive operation. Very colorful sponge, coral, crinoid combinations. Better wide angle ops than Bunaken.