Well, as far as the synths are concerned, the next time you open a Live synth, don't open it directly. Look for it under Instrument Racks. The reason I'm saying this is because if you take it from the Instrument Rack, it will sound more like a hardware synth preset because it will already have effects on it.
Almost everything but a true analog synth will sound thin and dry without effects. That's why no hardware workstations have sounds in it without effects.
As far as Operator is concerned, I understand what you mean. The GUI is kinda plain. Reason and Live are the exact opposites when it comes to GUI. Reason likes to give bright colorful graphics and pictures to look at. Live is no nonsense. That being said, I actually bought some videos on sound design for Operator.
http://nickstutorials.com/products/sound-design-in-ableton-live-operator
That's the only I could feel comfortable with Operator. The reason that the OSC's probably sounded different to you is because Operator isn't a Subtractive Synth. It's an FM (Frequency Modulation) synth. The OSC you were trying to tweak was probably being modulated by another operator. FM isn't as easy to learn how to tweak as a subtractive or even an additive synth is. Operator is actually a little misleading because even though it is an FM synth, it still has a filter section. The most popular FM synth of all time is the Yamaha DX7, and it didn't have a filter section at all:
http://www.maths.abdn.ac.uk/~bensondj/dx7/images/dx7_3.jpg