It's all about aerodynamics. Wing position is not as important as you think,rather more of perception and looks. Dihedral effect depends on both position and angle. Airplanes that we fly are normally setup with proverse roll or no roll coupling. Proverse means that left rudder will also induce a left roll. A classic example of not getting a design right was Dave Platt's Contender design for Top Fright, which has adverse roll with rudder input. This is a classic example that we sometimes see when a builder removes the dihedral from a low wing design. A high wing model gets a dihedral effect from the wing position, but it can also be setup for no roll coupling with anhedral on the wing.
The other difference between trainers and more advanced designs is contained in the decalage and balance of the model. Trainers are designed to be speed sensitive, pretty much the same as full size general aviation aircraft. Generally this means that the wing has a positive angle of attack while the leading edge of the stabilizer is slightly lower, along with a down thrust on the engine mounting. On top of this, is the CG is very far forward so that the nose will drop down as the airplane slows. So if the airplane is in a slight dive the extra lift brings the nose back up, and after a few cycles the plane will stabilize In level flight. So you fix the power at one setting and trim for level flight. Great for training initially, also good in full size when you are looking at maps. But the airfoil and wing position is not too important, and any design can perform in this manner, even an Extra 300.
Finally a word on wing loading and wing planform. You can get away with a lot more pilot errors with a light wing loading and a constant chord wing. An Ugly Stik or a Pulse are both very good at making pilots out of people that have solo'ed, but are low time fliers. They allow you to bang the sticks around and explore the art of flight without too many crashes where the airplane bites you in the arse. Your time with this level of aircraft should be doing thousands of touch and goes, inside and outside loops,figure eights, both horizontal and vertical, Cuban eights, split s's and Immelmann turns, spins, inverted flight including turns, rolls, snap rolls inside and outside, stall turns, and moe touch and go landings. No matter what you do in the air, blow the landing everybody notices. If your instructor can't fly these maneuvers find a new one after your basic training. Many seem to thing that instruction is over once you solo, but at that point you are about one to two years away from really being able to master the art of flight. Even then, you might be at a 90-95% level of flying ability. At this point it may take you hours of effort to refine something as simple as a loop, since a great loops requires changes in elevator input throttle management, rudder input, and a precise entry with the wings level.