Juliean said:
(otherwise, 32 bit would still theoretically be faster than 64 bit because their pointers are also only half size, wouldn't it)?

Using 32 bits to store a reference to something instead of a full 64-bit pointer is one reason one might choose to use handles rather than pointers - because you can fit more 32-bit or even smaller indices or handles in the CPU cache than you can 64-bit pointers. If you're in a situation where cache utilization matters (like, say, updating one out of thousands of different objects) then this may be an important optimization. If you're in a situation that is space-constrained (happens more often than you'd think at AAA scale) it might be relevant, too.

shared_ptr is something I don't typically recommend for other reasons, though. The requirement that the reference counter be thread safe is wasteful in single-threaded contexts or contexts where the synchronization is done at a higher level (eg. fork/join model) and its use frequently indicates that little thought was devoted to what should actually own the object in question.

I don't see GPU processing modes coming to the C++ core. I can see it easily as an extension.

The committee is protective about the language core, and for good reason.

It isn't for any specific machine, but for an abstract machine. Each group tends to think it was made for them, which is a good thing. It is made for desktop machines, it is made for supercomputers, it is made for minicomputers and microcomputers, it is made for microcontrollers found inside memory chips, hard drives, and wristwatches. It is made for satellite computers, for medical equipment, for microwaves and refrigerators. The language core needs to work just as well on an 8-bit 4 MHz processor with 2KB of RAM as it does on a 4096-node supercomputer with exabytes of collective RAM. The language core team tries their best to make it work EVERYWHERE, and provide functionality for ALL types of software.

The same is true about the C language core, with even stronger views than the C++ committee. Trying to bring it back toward the original subject, that's part of the reason for C's decrease in popularity. It still works, and you can still certainly use it for a 3D game and for virtually any type of software, but many features and implementations are more difficult to use for identical effect.