vertalop,
The Makila engine on the 225 is not new, it is a growth of the basic engine (this is not bad, it is good, as that engine is a reliable one, for sure!)
Like virtually all engines, it is designed for turbine blade retention, not disk retention. Blades weigh small fractions of a kilo, disks weigh several kilos. The "everything" that you saw retained were the light blade shreds, every engine has to do that.
To meet the current regs, and not be grandfathered, the aircraft has to maximize the safety of its design to allow fly home after the bursting of the engine turbine. These 1 to 2 Kg chunks literally shoot big holes in things, and when the engines are tightly clustered around the transmission, with the primary flight control rods between them, turbine bursts mean big problems. Perhaps you recall the dramatic footage of the L-1011 landing (cartwheeling into flames) at Soux City in the states years ago after the crew had to control the aircraft with the throttles (!!) and saved a large percentage of the passengers, this accident triggered the new rules for transport aircraft. This was proven a necessity for helos after an accident in the North Sea where the primary flight controls were cut after a turbine burst and the aircraft tumbled into the water.
The layout of components, redundant controls and passive shielding are methods of meeting this requirement. The purple ring on the S-92 shows the places where detailed shot-path analysis was performed, and how that area does not include the primary controls or servos. This was one of the reasons why that engine layout was selected, and also one of the reasons why grandfathering of old designs is necessary, since entirely changing the layout is impractical.
That being said, I do not know of any data to show that the EC 225 meets this turbine burst requirement. The type certificate data sheet will tell the story, by telling which paragraphs it meets and which it grandfathers.