...... I'll start with positive facts:
- it is a stunning place to visit (but there are plenty others globally)
- the resort is lovely (and there are plenty of others also - which are a lot better)
- staff are true pros who love what they do and take true pride in what they are doing and where they are doing it... almost unique in fact - though one or two were downright weird.....
BUT......
we were invited, in 2005, to produce their 2006 promo vid.... upon arrival we were obviously asked where we were from etc....
"What's Thailand got that's worth diving for?" came the replies from most of the staff there....
and in CERTAIN respects they could be right (although we had our very own resident Rhinopii on our local dive site last season!)
I won't state exactly what animals in our vid were taken from the harddrive but suffice to say that most of the guides were stunned to find how much of their presentation was being played out by a non-residential wakatobi (or even Indonesian) cast.... 
Strangest thing about Wakatobi that I found was a situation whereby all the staff and guests seemed to be suffering from a syndrome best described in the Emporer's Robe story by Hans Anderson - click here for full story - simply put, if you don't agree with us, then you're not in our gang...... maybe it was cos people had spent so much money, time and effort getting there that they didn't want to admit that SOME of the dives were purely mediocre.... 
I still didn't answer your question yet, sorry - nope, not a biggy in site..... biggest we got was the frogfish..... 
hope you have a great time there and please, if you've found a dive to have been "just alright" then say it! At least as a paying guest, they will be forced to respect your words....
at the end of the day, the stunning areas are drop-dead gorgeous.........
would i go back? only if they pay me, again.....
Chris