Mars has not been a favorite pick for a very long time. He is popular in Competitive Dota as it covers many ranged carry heroes. On average ratings, the peak of Mars = is a deliberate leak of the game. His win rate is below 47% in all divisions, so the hero is very weak, even in the hands of Divine+.
Mars is a very specialized hero. Despite his apparent simplicity, Mars requires specialization, just like Earth Spirit or Broodmother. It's challenging to take and win on this hero solo. In order to fully reveal Mars's potential, you need to be able not only to hit with a Spear but to hit it in such a way as to remove one or two opponents from the position simultaneously. At the same time, you need to know and be able to use different hero tips, such as the ability to skip the animation of turning in front of a spear by pressing Bulwark, turning in the right direction, and only then Dagger's Blink.
After a week of absolute pub domination, the hero is back on the bench. PA win rate dropped to 43% in Divine+ games, making Phantom one of the worst picks in the game. Some of the reasons are quite obvious. The hero has been made weaker, and her talents at 10th give mostly nothing.
Moreover, the players started to play faster again. Phantom prefers long games, so the higher tempo slowed her down. Well, it's worth noting that perhaps there was something undocumented in the last patch. PA has become weaker by 0.2 Strength and Agility per level, which means a total of six stats at 13-lvl. It's not very much. As well as losing 40 starting HP and one base damage.
Puck was getting quite serious nerfs two patches in a row, which, coupled with removing a small camp on the central one, made him noticeably weaker. He is still highly rated by Pro’s as few heroes have that much mid-lane control, but he shouldn't be played in pubs.
The main problem with the hero right now is that he doesn't work as well with the naked Witch Blade. The item is still mandatory to collect, but now Puck is not so strong in terms of fights before buying Blink: the speed of his Illusory Orb is not enough to take the correct positions in battles. Therefore, we end up with a mighty hero, who, at the same time, is not so lane-strong and cannot move to ganks quickly. That is why it is problematic to play Puck now.