The ETF share class’s expense ratio is 0.25%, which is less than your portfolio’s aggregate expense ratio of 0.2875%. And it’s not unreasonable for one to assume that Vanguard will lower the mutual fund share class’s expense ratios as the fund gets larger. Vanguard will convert shares’ class for modest fees. Even with a higher expense ratio, one has to weigh the additional explicit cost against the less monetized benefits of having one fewer fund. For example, if one were investing outside tax sheltered accounts, where capital gains make transactions undesirable and investors ought track cost basis on all purchases, one fund would make things a lot simpler.

Re: Rebalancing

Your criticism that “the country and region allocations will float on the whim of investors” is the advantage an efficient markets proponent would praise. How can one consistently hold the belief that markets are efficient in allocating capital between market caps or sectors but not geographic regions or currencies? Global Stock Index is only an extension of the same investing philosophy behind TSM and All World ex-USA, neither of which rebalances between their constituents (e.g., market cap, sector). All World ex-USA doesn’t allow you to rebalance between region or country. In essence you’re defending indexing but simultaneously claiming one can market time domestic vs. aggregate foreign.