People who think Legacy is wide-open need to dig under the surface a little bit. The format is very clearly tiered right now, and your chances of making top 8 if you don't bring a Tier I deck are fairly low.

Tier I: Counterbalance with NO, Zoo, Storm
Tier 1.5: Goblins, Dredge, Reanimator, Enchantress, Loam decks, Merfolk
Tier II and below: basically everything else

Really, there are very few good decks, but there are, like, eight million Tier II ones, so people assume you can just show up to a Legacy tournament, play whatever you want, and do well. The truth is, you'll probably end up with a bad to decent record unless the Pairings Gods bless you with great fortune and you lucksack your way into the Top 8. The perception that Legacy is some sort of wide-open field ripe for the breaking is artificial, and the fact that commentators and writers continue to espouse that viewpoint does newer players trying to get into the format a grave disservice. In legacy, you play a good deck, or you scrub out, or you sacrifice a bunch of virgins the night before and get super lucky.

An aside: Zoo is only Tier I here because it's popular: it's easy to pick up, straightforward to play well, and has a bunch of auto-win matchups that also happen to be popular decks. However, it also has auto-lose matchups that also happen to be popular decks, including the Loam decks like Lands, Enchantress, Storm, etc - in other words, decks that aren't interested in fair fights with dorks. Storm doesn't dominate the format because the blue decks hold it down, and Zoo decks that pair up against blue in the first few rounds will likely win and then dodge Storm all the way to the top tables. Zoo decks that don't meet blue decks in the first few rounds either auto-win against jank decks or get paired up against decks that are bad for them and scrub out.

The point here is that there are a lot of very viable ways to control combat in this format, either by ignoring it, locking it down, or tilting it heavily in your favor by cheating the biggest monster into play. All of the best decks aside from the aggro decks have a way to do something unfair, which doesn't help Zoo at all.

That was the point of the article. The metagame is very Rock-Paper-Scissors right now, but rogue decks that can dodge bad matchups can make it to the top tables and make the format appear more open than it really is. Goblins is probably not as good as people are claiming it is right now, considering how it's been around since forever and is only now putting up a good result again (MTGO doesn't count for a large variety of reasons).