Aluminium alloys are not yet history. There is still some potential in this materials. If it would be possible to combine the strength of some peak aged 7000 series alloys with the fatigue/crack growth properties of some 2000 series, the corrosion resistance of some 5000 and the weldability of some 6000 series alloys, then we we would not talk composites anymore. The effect of specific alloying elements and their combination has already in the past allowed to creaty totally new and superior alloys, there are probably still some more "miracles" around, which have just not been discovered by now. There a plenty of rare metals which have never been tried as alloying elements. The latest promising development are the Aluminium Scandium alloys.
Additionally production methods have still lots of potential. One aluminium manufacturer (pechiny if I am not wrong) has developed selective heat treatment methods using laser technology. This allows for example to produce a rear spar which upper flange is heat treated to maximum strength and the lower flange heat treated to maximum fatigue and corrosion resistance. It may as well be possible to cast billets which have different concentrations of alloying elements in different areas. Or just like we introduce additional semi-conducting material into silicon waffers during chip production, we may be able to locally introduce additional alloying elements into a part by means of diffusion. Or we may produce "laminated" aluminium, just like the famous samurai swords are forged from layers of different types of steel (soft ones, to make it flexible and hard ones to make it cut through anything)
If you look at the fuselage of the piaggio Avanti, you hardly believe that it is produced from aluminium. There is still a long way to go from riveted sheet metal to the optimum you can get from light alloys.