I think a starter kit instead of a rarity/type chance alteration may be the better deal imo. If pots are only for the chance at better land, then users will feel compelled to buy the potions to survey the land, which means your big hit rare lands are no longer as special since they chances are given across the board for all users who would purchase the pots, which would likely be pretty much everyone. ^^"

If we do a starter kit that supplies some sort of resources bonus to at least get a headstart for each plot, then that would feel like more progress than just a straight adjustment to the rarities, since we would be skipping straight into action with a beginner building per plot or something. Maybe it can even share the rarity function then still, but the rarity/type adjustment alone seems a bit redundant since the rarer of the lands and resources they would produce would generally just become less scarce/less demanded.

It should a fulfilling purchase, rather than what seems as an obligation.