I feel I should point out that diving a back plate and wing have nothing to do with the training company of GUE (Global Underwater Explorers) or DIR 'Doing It Right' philosophy of diving. You do not need any specialized training beyond your basic open water SCUBA course to dive a wing.
As people have already pointed out in this string, diving a plate and wing instead of a BCD has a number of advantages. However, that being said there is absolutely nothing 'wrong' about diving a BCD. I know plenty of tech divers that dive BCDs and can dive circles around the local cool aid crowd.
Personally I like the streamline profile my wing and plate offer, and the fact my plate and wing don't need to be adjusted every time I put it on. Other advantages are that I have no padding to both soak up water and add bouyancy (reduced lead requirements), customization options (infinite essentially), and ability to resize my gear if I put on weight or lose it ($20 in webbing)
If you are happy with your Stiletto there's no reason to run out and drop more cash on a plate and wing if you're looking to get into tech diving. I would recommend if you already have your gear just stick with it for now as there is no real requirement for a plate until you go to a doubles set. Once you get 100+ dives under your belt and you are sure you are going into diving for real start replacing your gear piecemeal doing your research and due diligence prior to each purchase.
Whatever you do don't let anyone 'bully' you into a gear purchase because you need to Do It Right. The best divers are thinking divers.