By now, it's not much of a secret that I dislike playing Modern competitively. I've had this opinion since the format was created years ago, and my reasonings have not changed. Modern suffers from a fundamental problem in that there are too many linear strategies and they are all extremely good, demanding a lot of specific sideboard hate, and then the game becomes about whether you draw that specific card or not, which is not fun for any player.
Let's look at the archetype breakdown from the PT:
We see that the most popular deck by far is Junk in all of its variations, at almost 30%. Then, the next most popular deck is Burn, which is 12% of the metagame. After that we have Infect, and that's already only 7% of the metagame. Then we have stuff like Affinity, Twin, Amulet, Scapeshift, Storm.
Most of those decks are what we would classify as “unfair decks"—they are hard to beat unless you specifically prepare. Most of them are also very easy to beat if you do prepare. The problem? There are too many of them, and you can't prepare against everything.
Take Affinity. Affinity has a good game 1 against most of the format, but it really struggles with cards like Creeping Corrosion and Stony Silence. That's not to say it can't beat them—it can—but it's very hard. Martin Juza, an aggressive mulliganer, kept a hand of 6 lands + Stony Silence against Affinity at the PT because he thought the card was that good. I can't imagine many other 6-land hands Martin would keep.
So, you have a deck that loses to Affinity? You can fix that—add 3-5 sideboard slots that are dedicated to combat it. The problem? Affinity is only 7% of the metagame. Assuming win percentages are equal, there is about 50% chance you don't even play against Affinity in a 10-round tournament.
At this point, should you even dedicate sideboard slots for Affinity, or should you just hope you don't play against it? Storm was 2% of the metagame. Should you play Rule of Law if you're 80% likely to never play against it? Probably not. How about Amulet hate? Also probably not. Even with the second-most-popular deck—Burn—you're still about 30% to play against it zero times. Even if you predict correctly that Burn will be the most popular of the “combo” decks and sideboard against that, there is still a decent chance you never get to use your Kor Firewalkers or Feed the Clans.
So we get to a point where you need sideboard hate to beat anyone, but you're not incentivized to have it, because you're not likely to play against any deck many times. Since you only have 15 sideboard slots, the best strategy is to simply choose three or so decks that you want to beat, and hope you dodge everything else. I do not think this is a healthy approach to a competitive format.
You could argue that you could just play an unfair deck yourself and pass the burden of “correctly guessing your matchups” to your opponent. That would work, but you are as much a victim of randomness as you were before, because now you have to dodge the people who chose to beat you. It doesn't matter if I'm the guy without Rule of Law hoping to dodge Storm or the guy with Storm hoping to dodge Rule of Law, it's still all about matchups, sideboard cards, and drawing them.
The banning of Pod and Treasure Cruise exacerbated this problem tremendously, because now two of the decks that had general answers are gone. Pod could play things like Thoughtseize, and Delver could play things like Spell Pierce and Negate, which don't require specific pairings to be effective. Now, the only deck that's left is Junk, which is the deck that combines pressure with generic disruption. This is the reason Junk was 30% of the metagame—it was basically the only choice for anyone who did not want to play a combo deck.
I don't know whether this can actually be fixed. You can't ban every card in any combo deck, and if you unban cards from other fair decks, there is a chance they will just take the role that Junk now plays (and that's a role that has been held by Jund, Pod, and Delver before). I think the second option is the best bet, though—they should strive to make multiple fair decks equally good.
The first order of business for this, in my opinion, is to unban Ancestral Vision. I do agree Cruise was too powerful, but we need some sort of cheap card advantage so that blue decks can afford to a) compete with Junk and b) run enough cheap answers and still compete in card advantage in the late game. After that, I would probably unban Jace, the Mind Sculptor and Bloodbraid Elf. Those could potentially be harmful, but I think the format is bad as it is, so it's a risk I'd like to take. This would probably create a scenario in which there are at least two viable fair decks: blue-based and black-based. It's not enough for me, but it's a start. It's also possible that it creates a scenario in which blue is just better than Junk, in which case blue will be the new 30%, and that would suck.
Another possible solution is to expand the sideboards for Modern. Other than maintaining consistency, there's no real reason why sideboards have to be 15 cards in every format. 15 is a made-up number, a relic from decades ago when Magic was much different and the Modern format did not exist. If you could play, say, 20 sideboard cards in Modern, then perhaps you would be able to afford specific hate against the great majority of unfair decks.