100% VWCE for a 30+ year horizon, does it actually make sense, or are there better options?

Curious how people think about ETF strategy for very long time horizons (30-35 years).

A few things I keep going back and forth on:

**1. Does broad diversification beat concentration over a 30+ year runway?** The standard passive case for something like VWCE is hard to argue with. But if you have enough time to ride out volatility, does a more concentrated approach (heavy US, heavy tech) actually have higher expected returns historically, or does VWCE's diversification win out?

**2. Does the AI/tech boom justify a tilt, or is it just performance chasing?** VWCE is already \~65% US and tech-heavy. Adding QQQ or a sector ETF on top means doubling down on what's already the biggest weight. Is there a real thesis for doing that, or is it just recency bias?

**3. Factor investing vs. simple market cap: what does the evidence say?** Small-cap tilt, value tilt, slight leverage (e.g. 2x ETFs), for a horizon this long, is there a factor-based approach that has stronger theoretical backing than just holding market cap?

Not asking anyone to review a specific portfolio, just interested in how people reason through these tradeoffs.