yes.
can you image a UN where USA has no veto? of course not, because if UN did gave veto to USA,USA would found another club to take the place of UN. at that time ,UN would be worthless as "league of Nations" in 1930s.
So,Before a Enthusiastic UN reformer as strong as USA were to appears ,it would be impossible to increase the veto's on UNSC.
However, in forseeable future,none of Japan,India ,German or Brazil could become powerful enough.
Instead, ,current vested-interest-keepers such as USA and China are going to be more and more powerful.None of them is enthusiastic to delute their vested privileges.
Fact is that None of Big 5 is enthusiastic to delute their vested privileges,Italy,Pakistan,Mexico are just the proxies of big 5.
Largely agree with you, but have to add a point
In the case of Japan, her arch obstercal is neither of economical origin nor of WW2 aspects. The very thing that prevent Japan enter this club is America itslef.
One key factor of the club is that being an power with veto, you must have an INDEPENDENT deplomatical aggenda and an INDEPENDENT military power.
That is to say, being a 'vessel' of another country while holding the veto power at the same time is not possible. Because no other power would willing to see US holding two veto on the critical issues. For US can simply use Japan's veto as a shield to share the moral burden or he can just stay behind play the puppet master. That would not be the interests of either China russia or Fra, BRIT.
Therefore, Japan has to prove that her vote is out of her own will and cannot be puppet by US at critical situation.
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For india, I can only say that keep a healthy distance from US may prove more benificial than embracing it completely, for US has only one veto of five. You have to figure out what kind of force you want to represent in the UNSC. For democratical nation, there are US and UK; for 'undemocractical' nation, there are Russia. For developing nation and africa nation, there are China; For EU, there are FRA. You have to figure out what kind of voting-bank you want. Just saying the biggest democratical blabla```wont solve you any problem if you cannot represent them or do not have the power to uphold their interests.
The most likely voting bank is democratical-developing nations. However, for democratical-developing nations, they already got all the representation they want from the big 5, and taking india's power globle into consideration, you really cannot do much for them. For your power globle has yet to breach the surrounding areas.