I'd still prefer iron sights and a longer barrel, though. I agree with you...when I think RIFLE I think of a classic "shootin' iron", not a sci-fi prop. However, there were probably a lot of guys saying the same thing about the earliest M16s.
My dad once told me that you know you're getting old when you start not liking new stuff.
The problem remains that M16 magazine well that requires a straight section of magazine inside the well, transitioning to a curved configuration outside the mag well, the cause of most M16 feeding failures- as it is on the Armalite AR18, Galil with M16 magazine conversion [the Galil prototypes used Stoner 63 magazines, which work] and other weapons using the M16 magazine.
Box magazines for the M16 were made in 25-round capacities, similar to those used for the first versions of the French FAMAS F1 bullpup, one good answer to the M16s lower configuration. And with a cartridge change, that might well be made to work just fine with the M16A1/A2 lowers.
Or a new weapon alltogether, probably using plastic magazines, can be used. I've been pretty happy with those of the AK74/AN94 in the Russian 5,45mm caliber, so it can be done. And I wonder if one answer might be opening the Russian 5,45mm to use a .276/7mm bullet, a nice compromise between the 6.8mm and the original Kalishnikov 7,62x39mm- and very reminiscent of the British .270/30, [AKA the 7x43mm] for which the original test versions of the British FALs were chambered, dropped for the 7,62x51mm NATO instead. The Brits may have had the right idea all along- and in the bullpup British EM-2, the cartridge was said to be capable of dropping a man at 700 yards. The Brits were still keeping their claws hooked into their global empire then, and from India to Kenya, Malaya to Kenya and Rhodesia, a reliable automatic military rifle was still a necessity.