Many of the draws from Mono-Blue that feature Nykthos are quite poor, as it doesnt help you cast your two- or three-drops all that well and basically just combos with Cyclonic Rift (which Hatch also cut)
With several new cards (including a few new commanders), a release date, format legality, and several other aspects of the Spider-Man set now confirmed, fans have a lot to look forward to
Cards that say "win the game" are scary, so this makes you a threat
Alongside being powerful and effectively free removal, Solitude will be an absolute menace in blink-heavy decks like Yorion, Brago or Roon, where you can easily repeat its enter-the-battlefield effect to keep removing creatures as much as you need
[1] This is a huge advantage since the vast majority of ways to destroy a creature require targeting it