It is not that hard to play as Hunter, though the game does favor Challenger slightly. But I think people complaining about game balance are exaggerating a bit.
After a while the game gets a little stale as there is only one map (or possibly 2 or 3 that all use the same aesthetic) and it is 1v1 so theres no exciting team gameplay. But it seems they will add more maps later.
Some rare characters have good abilities but some do not, and some common characters have good abilities too. It is not P2W as you can win with your favorites.
The game is extremely stingy with jewels outside of the 2000 they gave for the game basically being unplayable for the first two days after launch. It is rare you will earn more than 10 or 20 jewels after playing for a long time, and a 10 pull costs 1500. If you want to buy those jewels it will cost you 3000 yen.
Overall those are my main complaints with the game to warn players what they might not like. But overall I am really enjoying the game. I expect it to only get better from here on out. As they add maps and fix the connection issues the game will surely thrive in the future. Even if it is a bit of a rough start.