Good points,
I think they should first concentrate on the diff cup/cvd/dogbone strength issue (a slight redesign and slightly better grade steel will almost cure this problem).
On that issue I think the only saving grace for cen is that is that they built the weak spot into the car in the right place if you look at it this way - the diff cup is the cheapest part of the drivetrain (and easy) to replace. But they just built these components too weak. We dont mind things breaking after major crashes, its just (CEN) we get @#*%ed off when things break to often.
I think the easiest way to cure the chassis flex is to have some sort of full length top deck on the chassis setup - see forum "MT2 Chassis Modification"
As for the engine, I think the NT-16 is way good enough for an entry level machine, half the fun is modding these things yourself (as long as the purchase price reflects the need to mod if you know what i mean). And the cheapest way is the .18 piston/sleave/rod upgrade.
Definately upgrade the steering servo on the stock machine, this is just crap, mine busted after running in the engine, and it wasnt worth the hassle for me to claim under warrantee and for what, another crap servo!!!!!
Re-design the mount for the boby posts, this thing likes to pop wheelies

on rough terrain (in standard form) and (the rear one) breaks really easily.
One last thing, the standard screws could be of better quality steel aswell, when they are loctited in (from factory) i was rounding them, and Im no amature when it comes to screws!! Man for 18 bucks I got a stainless cap screw set from RC Screws!!! Cmon CEN!!!!
I may add to this list..........just my thoughts anyway.........cheers all