I think they try too hard to be original sometimes, especially with the interior bits. Exterior wise, I can live with what they have currently, but for me, the interior is very important, as thats where I will spend the majority of my time with the car.
Copy the market leaders, basically do what the others are doing.. There is no such thing as 100% "original" design today. Someone has already done something out there, its just how all the elements are brought together to make a complete package.
If a new proton comes out with a "Toyota" type interior, I dont think any prospective proton buyer is going to complain.
ERGONOMICS.. very important. The Satria Neo, once you've adjusted your driving position, its very difficult to get to the doorlocks, seatbelt, and power window buttons. Steering wheel design is irritating, just go with a regular steering wheel with a rounded grip rather than the current "squarish" grip. Seat design in the current waja and gen.2 lacks underthigh support. Savvy and Neo seats are a step in the right direction. In general, their seats are too high as well.
STORAGE... the trend today is storage. people want lots of places to store their things. Proton's minimalist lotus influenced design is great for a lotus sports car, but its not good enough for everyday cars, especially family cars like the waja.
Most importantly, KISS (keep it simple stu***)