thing is, Russia having veto power is a relic of the past. Having GDP far smaller than Italy, let alone other EU economies.
It's nothing to do with the size of the economy. But you're right that there is something out of date about which countries have veto power.
If we adopted the true principles underlying the original list, then India, Pakistan and North Korea would have a veto.
Hint: would you rather Russia vetoed a proposal or nuked the countries making the most fuss about wanting it?