Alcaraz has much more variety and can handle sinner's weight of shot. Alcaraz also is nowhere near peak yet either, sinner is now at his peak. That rivalry will be one sided.
That's not what a gatekeeper is. A gatekeeper would lose consistently to the whole top 5-10, not just to Alcaraz. Nadal wasn't a gatekeeper in 2011 when he lost several finals to Djokovic, he was basically still above almost everyone else.
Anyway, bait thread, and I posted in it, damn me.
Yeah, because most gate keepers are ranked #1, won 2 slams during the calendar year in question, have the most match wins, and have the best overall winning pct. Sinner is the perfect example of a gatekeeper.
Another excellent example of a gatekeeper is 2006 Federer. He was 2-4 vs Nadal. He was absolutely the gatekeeper that year. There's absolutely no doubt about that one.
Here are some other excellent examples of gatekeepers. I will limit this to a surface.
2015 Djokovic. He was the gatekeeper on hard courts that year. Why? because Ivo Karlovic was 1-0 vs Djoker on hard courts. HTH is everything. You see, HTH for a season is a MASSIVE sample size. The rest of the reason is meaningless.
2017 Federer: He was the gatekeeper on grass courts and hard courts that year. Why? Because the combo of Donksoy and Haas went 2-0 against Fed.
2011 Djokovic: He was gatekeeper on hard courts that year. Nishikori won the HTH that year against him.
2004 Federer: He was gatekeeper to the gatekeeper on hard courts. He had a losing record to Hrbaty and Berdych that year. Honestly, getting owned by those two guys means that he was likely ranked outside the top-200 on hard courts that year. Hell, I was better than Fed that year. I didn't lose a single match to guys like Hrbaty and Berdych. I think that Fed should have been kicked out of tennis for sucking so badly that year.