3rd Gen Hardest Kanto Gym Leader ?

[Kurapik]

I picked Sabrina because there isn't a fast way to level up Gastly; I encountered some difficulties againist Misty too, but I always catch a Pikachu in Viridian Forest and also I make sure to have a Buterfree so i can poison/fall asleep her Starmie while Pika make him fainted

 

[TheSecondComingOfCaterpie]

Misty was always the hardest for me, because even when I pick Bulbasaur, if I don't grind, the speed and Special Attack of Starmie mixed with the annoying second effect of Water Pulse drove me crazy.

 

[Jin Of The Gale]

Charmander was my starter so, like everyone else, Misty was hard for me to defeat. I caught a Pikachu from the Viridian forest but it got killed by Starmie before it could do anything. :/

 

[Deceit]

In my playthrough of FireRed, I had used a Charmander as my starter, and I kept losing to Misty. I had to train for a really long time until I finally managed to beat her Starmie. I still remember my frustrations with her, and it felt like winning the lottery when I beat her.

 

[ZetaZaku]

Sabrina was tough in the originals, but she's really weak here. All you need is a Pokemon with Bite and that's a common move. The rest is also way too easy in the remakes.

 

[nouchken]

I used to have difficulties with the 'brainbraker' of LT. sturge back in the period when I was 6.

Gym leaders? I always used to battle Brock with pidgey and pikachu back then.
And I always succeed with some difficulty...

 

[RoreyG]

None of the were a problem my Bulbasaur soloed pretty much till 3rd gym were it evolved in the ship were you Venusaur and became even more beast I caught a Growlithe and evolved it into Arcanine for the 4th gym, My Alakazam took the 5th gym, Arcanine bited that gym to death together with Gyarados, Gyarados overpowered Blaine and Giovanni was taken out by Venusaur and Gyarados.

Gamefreak knew everyone would have a Charfetish thats why misty was the hardest but not from me, I completed the game weeks before my classmates (rivals) because of the fact that they were stuck at Misty while I was kicking Koga's ass

There's nothing wrong with Charmander. What you did is over-level your Pokemon (seriously, a Venusaur before you got to the third Gym). Hell, I could destroy Misty's Pokemon with flamethrower if I had a Charizard by the time I fought the second gym. Its not skill or smarts that got you through the game, you over-trained.

On to the topic. If you think about it, any Gym is easy to beat once you know what you're doing.
If anyone actually stopped to think about it, you would realize that in most cases (in every Pokemon game), you can catch Pokemon in the areas surrounding those Gym cities (or earlier on) who have the type advantage over the Gym Leader.

Mankey> Brock

Paras/ Oddish/ Bellsprout/ Pikachu> Misty

Diglett/ Dugtrio/ Graveler/ Sandslash> Lt. Surge

Pidgeotto/ Fearow/ Growlithe/ Vulpix> Erika

Rhydon/ Graveler/ Onix/ Dugtrio/ Kadabra (Abra early on)> Koga

Haunter> Sabrina

Any Water/ Ground/ Rock Type Pokemon available prior to reaching Cinnabar Island> Blaine

Any Water/ Grass Type Pokemon available before the 8th Gym Battle> Giovanni.

 

[Skyrath]

I used to allways find Lt.Surge hard because I usually pick water pokemon, and I don't really use any of my early Pokémon later on (Apart from Abra of course)

 

[Cerberus87]

There's nothing wrong with Charmander. What you did is over-level your Pokemon (seriously, a Venusaur before you got to the third Gym). Hell, I could destroy Misty's Pokemon with flamethrower if I had a Charizard by the time I fought the second gym. Its not skill or smarts that got you through the game, you over-trained.

Seriously, I don't know how people manage to get such high levels so early into the game, they must cheat or something. I was reading a FAQ in GameFAQs and the guy had L60 Pokémon when he fought Giovanni in Viridian, that's almost unimaginable to me.

On to the topic. If you think about it, any Gym is easy to beat once you know what you're doing.
If anyone actually stopped to think about it, you would realize that in most cases (in every Pokemon game), you can catch Pokemon in the areas surrounding those Gym cities (or earlier on) who have the type advantage over the Gym Leader.

That's usually my strategy in Pokémon games. Actually, in FRLG, they went to such extent that they not only gave Charmander Metal Claw, they also added Mankey to Route 22, which learns Low Kick and destroys Brock's Onix. And of course Mankey doesn't become useless after the second gym like Butterfree.

Examples of clever map placement in FRLG:

Brock: start with Bulbasaur/Squirtle, or catch a Mankey
Misty: Route 24 has Bellsprout/Oddish
Lt. Surge: Diglett's Cave just east of Vermilion
Erika: Growlithe/Vulpix east of Celadon, also Pidgey/Spearow literally everywhere
Koga: Safari Zone has Rhyhorn, Nidorino, Nidorina, all of them good against him
Sabrina: Gastly in Pokémon Tower
Blaine: Seafoam Islands with tons of Water Pokémon just before Cinnabar
Giovanni: By this point you should have something to beat him

Examples in other games:

GSC: Ice Path before Dragon Gym
RSE: Not sure, been too long since I last played it
DPP: Eterna Forest with tons of Bug and Flying Pokémon before Grass Gym
BW: Desert with Sandile (Ground Pokémon) before Electric Gym
B2W2: Never played it

 

[RoreyG]

Examples in other games:

GSC: Ice Path before Dragon Gym
RSE: Not sure, been too long since I last played it
DPP: Eterna Forest with tons of Bug and Flying Pokémon before Grass Gym
BW: Desert with Sandile (Ground Pokémon) before Electric Gym
B2W2: Never played it

RSE: Shroomish and (in Emerald) Marill before the Rock Gym

B2W2: Almost the same as BW with a few additions:

Riolu available before the Normal Gym
Magnamite available before the Poison Gym
Desert Resort before the Electric Gym
Chargestone Cave before Flying Gym
A lot of Electric and Grass Types available before the final Water Gym

 

[pikakitten]

Brock was the hardest for me xD I had Charmander and a few others so I had to epically grind but by then everyone got owned xD

 

[Cerberus87]

Oops just realized I didn't answer the question... Sabrina would be hardest for me. Misty is fairly easy with Gloom/Weepinbell and Sleep Powder.

Sabrina may have the same levels as Koga but it's wise to do her after him because Psychic is much more dangerous than Poison. Koga spams Toxic, but otherwise has no real way to attack you, while you can heal yourself with Full Heal and keep attacking him until you win.

 

[Capt. Pika]

Whenever I play the first generation I choose Charmander! And then I have to envolve it before I fight against Brock. This takes time and that's why he's the hardest leader for me.

 

[Pothus]

I'm surprised the majority is Misty. I found her quite easy to beat now (and as a child).

I chose Koga because poison types down-right piss me off. Specifically Koffing. Even more specific his Koffing.

I mean... just look at it!

 

[CrystalRose]

I'd say Sabrina because of psychic types.

 

[Venitardus]

Sabrina was for me due to either under leveled and/or because my poke's were weak to her

 

[Sweets Witch]

Koga or Sabrina. Muk was a pain every time, but I had terrible luck with Sabrina and I'd end up losing because of the slightest error.

 

[Caelus]

The only gym leaders I remember struggling against were Erika (when I chose squirtle), Misty (when I chose charmander) and Sabrina. I didn't think the others were that bad, not even Koga.

 

[Halipoke]

It's Sabrina to me, and it seems I'm not alone in this one. I never had any defences against her, and her Pokemon were so fast... I always saved her to be my last gym leader.

 

[jaydezzal]

I'd say Sabrina. Koga's not really hard, he's just cheap with his Minimize spamming. Sabrina's Alakazam, on the other hand, is pretty fast and can one shot most anything with Psychic.