the only simple way to change the current system would be to make the lower grouped numbers pay a higher dividend for instance 3 numbers now pays £10 and so on , under a new system the 3 numbers would pay " for instance £15 " this however would have a large nock on effect to the higher stakes that could be won , reducing the jackpot considerably.
however it should be noted that there have been occassions when a large number have won the " jackpot" and the 5 number winners have won more than the 6 number winners.
the higher the " jackpot " the higher the number of players would play so reducing the higher winners stake reduces the number of people playing . and reduces the amount of funds in the pot for all potencial winners.
sadly its a circle cercumstance . any changing would obviously cause other issue's and problems , im not sayin insumountable problems but anything that that would need a higher level of organising would obviously lave itself open to calls of " fixing " and unfairness. Although the current system is not exactly good at spreading out wealth it is currently the easiest system to impliment and the fairest way to find a winner as well as gain the income that it does.