Also I don't get Groundskeeper yet. I like the card a lot but I never had lot of VP with it. Wild hunt seems way better to me. Can someone explain me why groundskeeper is so good ?
Perhaps the best way to explain Groundskeeper's power is with the following analogy:
Groundskeeper is to Goons as Highway is to Bridge.Goons and Bridge are both excellent payload cards in their ability to create explosive VP generation and cost reduction respectively. However, both are terminal stop cards and require a lot of actions and draw support (i.e. a big engine) in order to maximize their multiplicative potential. Highway has similar cost reduction benefits as Bridge but since it's a cantrip, it's
way easier to get six Highways in play than to get six Bridges in play. To compensate, Highway also comes with a few more restrictions than Bridge (no +$ or +Buy and non-throneable cost reduction). Groundskeeper likewise grants similar on-gain VP like Goons, in a sleek cantrip package, but also with restrictions (no +$ or +Buy or attack and only works on VP card gains).
In practice, Groundskeeper basically gives players the ability to very easily overtake a fast money strategy in VP--play five Groundskeepers and Estates become Provinces. With multiple gains, Groundskeeper is absolutely bonkers, capable of generating of Goons-like insurmountable VP leads in a single turn. Except on sloggy, attack-heavy boards and in cases of much faster rushes/combos (e.g. CH/TF or Lurker/HG), not contesting Groundskeepers is often a losing move since unless you can quickly end the game, the Groundskeeper player will eventually win. In games where both players go for it, winning the split is critical. Especially early in the game, it can seem hard to justify repeatedly paying $5 for what's just a vanilla cantrip until the late game, but trust me, it's worth it (Groundskeeper makes $5 gainers like Altar and Duplicate really nice). Finally, unlike Wild Hunt (which is also an excellent payload and draw card), Groundskeeper-driven payload doesn't need villages to be viable.
For a game example, I humbly present
a dual-set tournament game against Burning Skull (game 2 starts at about 24:15). I'll admit this was before I really understood how good Groundskeeper was, but you can see Burning Skull pull off a dramatic comeback with Groundskeeper against my (bad) money strategy.
All in all, Groundskeeper is a subtle but deceptively powerful card. I wouldn't be surprised to see Groundskeeper jump up another ten positions (or possibly more) in the next year's rankings.