Another perspective from somebody who works in a dive shop here...
For many of the reef dives, 18m/60ft is a good maximum; there's plenty of light, in some cases there's not much reason to go any deeper as the coral starts to break up. Even on sites where there is deeper coral, we're mostly interested in enjoying nice, easy, relaxing dives for as long as possible - people obviously manage their air a little better at these depths and therefore even relatively inexperienced divers can enjoy a nice hour-long dive.
Some places, such as car pile and Superior Producer obviously require that you dive deeper (30 - 35 metres) but I firmly believe that unless there's some specific reason you need to dive deeper then many of the dive sites are best observed from shallower depths.
As for boat dives and shore dives - it is often the case that the boats will visit dive sites that are readily accessible from shore anyway. Yes, some sites are only accessible by boat but either which way you decide to go, you're not going to miss out on a great deal should you choose boats over shore or vice versa.
Also - as Andreas said, you'll find a lot of the wildlife in the shallower water anyway. Every turtle and Eagle ray I've seen here has been in 12m/40ft or less, and we regularly find some pretty amazing stuff in less than 3m/10ft of water.
Diving deep is fine - but in most cases on Curaçao, that just means you're missing out cos you have to surface earlier!
*plink plink*
Dive safe,
C.
