Is non US equity a good idea for international diversification

I have a 75:25 equity debt split current and am looking to move 15% of the Indian equity to foreign holdings

Reasons are

1. Getting close to retirement(10 years away) and want to reduce volatility
2. Had it as ppfas was my only fund for a long time but had to reduce it in favour of hybrid funds
3. International companies are a lot cheaper than Indian equivalent in a lot of cases, eg suzuki vs maruti, google, microsoft vs Infosys, TCS etc

I lost hope of the RBI lifting restrictions and have decided to invest directly via vested

Broadly I wanted to narrow by option between the US market and all world

Drawbacks of all world is

1. I don't want china and (more)India exposure
2. Growth generally is lower in ex us developed markets
3. Withholding taxes on non us equity

On the other side the world has underperformed the US since 2009 and this might reduce volatility