Hoenn's array of Ground-type Pokemon is honestly quite impressive.
Most of them are at least competent, while others are out of this world. It's hard to settle on a list of the worst of them.
This list isn't just about Pokemon that underperform in battle. This list focuses on Pokemon that don't meet the player's expectations for what they should be capable of or what they should do as a Ground-type. Any Pokemon catchable in Hoenn is eligible for this list.
Note: This article is subjective and reflects the opinion of the writer.
3 most underwhelming Ground Pokemon in Hoenn
#3 - Camerupt
Camerupt doesn't do as much in the Hoenn region as it could in most other places, leaving players with a pretty disappointing experience.
Numel, the pre-evolution of Camerupt can't be acquired until about halfway through the game's story which, unfortunately, is shortly before the player starts to treck through the 1/3 of the map that's covered in water.
This water, naturally, is full of Water-types and Water-type using trainers. Which Camerupt is 4x weak to. The eighth gym is a Water-type gym as well, and in Pokemon Emerald, so is the Pokemon League Champion.
Any Pokemon that's 4x weak to Water is going to have some difficulties in Hoenn. It's unfortunate, but Camerupt is simply a casualty of Hoenn's Water-type prevalence.
#2 - Golem
Golem meets the same problem that Camerupt has in that it has a 4x weakness to Water. However, Golem has a couple of other unfortunate quirks as well.
Golem is much harder to acquire than Camerupt. While Camerupt requires just leveling, Golem needs to be traded (after leveling Geodude until it evolves into Graveller) to evolve. Many players simply don't have the ability or chance to trade Pokemon with others, making Golem more of a rarity than anything.
Players would expect a Pokemon of that rarity to perform well. But for all the same reasons that Camerupts underperforms, so does Golem, making the effort to obtain it ultimately feel wasted.
And neither of its abilities are particularly worthwhile. Sturdy is next to useless in this generation and Rock Head doesn't do much for Golem specifically. Gaining the ability since previous generations really didn't do much for Golem.
#1 - Nincada
Nincada is generally just a lackluster Pokemon.
Its design is just a basic bug, it evolves at the low level of 20, meaning it's not around for long, and neither of its (potential) evolutions even retains its Ground-typing.
Nincada honestly doesn't feel or look like a Ground-type, and that in itself makes it quite underwhelming as a Ground-type Pokemon.