Let us take it flight system by flight system:
1 - The main rotor:
Though they use the same type they are different in the very important regions that handle the many forces involved here. To handle the much greater forces that will be involved with hard 3D at higher rotor speeds, with longer/heavier blades, the Falcon and Raven have a very important difference in the feathering spindle area. instead of a 5mm spindle and only two radial bearings in the rotor grips, the Raven and Falcon SE comes with a bigger 6mm spindle and not only the two radial bearings, but also a thrust bearing in each grip. IMHO this is a BIG difference.
The mainrotor hub is responsible for transferring ALL flight forces generated by the rotor blades to maneuver the mainshaft, and consequently the body, to whatever attitude these forces are directed to move it. Consequently the base of the rotor hub is where all of this work is done. Here you find the Raven has a similar hub to that of the Predator. It is not a GRP unit like the Hawk or some other 50's. But it is a CNC machined unit that also has a clamping system at its' base that insures no rocking slop develops here. Again IMHO, a big and important difference.
2 - The flybar system:
Again an important flight system. Here on the Raven 50 & Falcon SE, one finds a very rigid system. This is very important in how fast commands generated by this system is transfered to the blade grips, be them commands to stabilize it in winds or to more precisely transfer cyclic commands from the swashplate to the blade grips. Their system does not use the more flexible 3mm flybar and more flexible separate flybar control arms, but they use a more rigid 4mm system with the same rigid flybar control yoke as on the Predator - again a big difference.
Also there is a very different set of flybar paddles provided with the Ravens & later Falcons. The smaller ones with the adjustable weights on the Hawk are more for training and sport flying then for 3D. The bigger ones on the Raven/Falcon, with the different airfoil, are much quicker, while providing the same, or better stability.
3 - The Swashplate:
This is another very important part of any helicopter's control system, as it transfers ALL commands from the servos to the rotor head, and absorbs all the forces from the rotor head. Here again is a big difference. The Raven/FalconSE comes stock with a CNC machined swashplate that is an upgrade item on most other 50 size helis. The Hawk does have a great swashplate for a 30, as good as or better then most swashplates found on other 50 size machines, with a CNC inner star, but with a GRP lower star. Ultimately the higher flight loads of a 50 size heli will start working slop into the fit of the bearing and uniball system in a GRP lower star, while not so, if it is properly fit into a machined lower star.
4 - Mainblades:
Again these are very important flight components. Though the woodies of the Hawk are some of the best woodies I have ever flown, they are still no match for the stock composite units supplied in the Raven/Falcon SE kits.
5 - CTD (Constant Tail Drive) auto-rotation system.
Again, this is a far more expensive system then the standard type provided with the Hawk. Kind of hard to do any backwards or aerobatic autos without a CTD system. So here again is an important and costly flight system difference.
6 - Clutch bell:
The Hawk's GRP clutch bell is more then adequate to handle the power of 32 to 40 size engines, but would be taxed by the power of the current 50 size engines. Consequently, the CNC clutch bell in the Raven/Falcon SE is another important plus compared to the Hawk.
7 - Landing gear:
The Raven/Falcon use the same heavy duty wide stance landing struts as does the Predator. Much more support on the ground and much harder to break - an important difference (Mind you I do wish they would result in a higher stance, I always put spacers to raise the heli on mine)
8 - Tail Rotor:
Here again is a very important and noticeable difference. As the tail rotor workload will be substantially more with a higher rotor speed set up (the tail rotor will also be spinning faster)and because many of us may want to use longer tail blades (as long as 95mm) I really like the fact that Century chose to include the tail rotor from the Predator in their Raven/Falcon, rather then the one from the Hawk.
Here you have a tail rotor that is better then some found on a number of 60/90 machines. The hub is not only machines from steel, making it much stronger then an aluminum one, but machined into it, are the spindles for the blade grips. Unlike most other tail rotors, the spindles are NOT the bolts that attach the blade grips, that easily can break from fatique and throw tail blades. A hub with machined spindles is by far the best IMHO.
Here you will also find that the blade grips rotate on these spindles while supported by TWO radial bearings, making for very smooth and precise pitch changes. This makes your gyro's job a lot easier. Also included in each blade grip is a thrust bearing to take the cetrifugal loads, again making everything smoother and the job of your gyro a lot easier.
8 - Torque tube:
The torque tube in the Hawk is an aluminum one with a dog-bone only at the front end. This is fine for use on 30/40 engine power and 85mm tail blades, but for longer blades and more power, it is again nice to see the same system from the Predator in the Raven/Falcon SE. This system also has a dog-bone at the back end, and is made of stainless steel tubing to better handle the extra power loading.
In my view, these are all substantial changes, and due to all these major differences, in all the major systems that handle the different forces that FLY or land the helis, I think they make the Ravens and falcon SE's substantially different helis from the Hawks.
Many other manufacturers would give new names to any of their helis that had evolved so much, and would have submitted each evolution to all magazines for a new review as they happened. Unfortunately, Century doesn't do that, so many may not clearly see or understand the differences. So I hope this helps more of us understand the importance of these changes.