Kyro3 will remain 100% efficent, thats why this chipset has made major waves. One major inefficency of graphics cards spouts from having to render non-viewable sides of a 3d image, with a tile based architechure it doesn't render this useless information therefore I don't see how efficency is an issue for kyro. But I suspect it is also extremely hard to design and get one that works properly.
It wouldnt bother me at all if kyro3 didnt even have TnL because of the power it would be capable of. Look at kyro2, not having the big NVs TnL hardly shakes it. Like some other guy said, I thought the current problem with 3d was bandwidth not transform and lighting. Hardware TnL would be offloading another load off the cpu in a attempt to make things move faster but if they hadnt near maxed out immediate mode rendering in recent times they wouldnt have to resort to more 'features' anyway.