I deeply regretted selecting Chikorita in a Soul Silver playthrough. I knew that I did not have an advantage choosing Chikorita, but I already played through the original Gold and Silver games with Cyndaquil and then Totodile, and was open to the idea of a change this time. I started off excited to get Chikorita because I actually think this line is the nicest-looking of the three Johto starters, so I was looking forward to having such an attractive traveling companion since it's sprite would be following me in the overworld.
My dream quickly turned into a nightmare. I understand that Johto wanted to introduce gyms with types that weren't previously in Kanto like ice, flying, ghost, steel, bug, dragon etc, but by doing this they unfortunately also created a situation where the region's grass starter Pokemon didn't have a single good gym matchup. Even back in the old RBY games Charmander or Pikachu weren't as bad in their region type-wise as Chikorita is in its region. Though they weren't as good as Bulbasaur or Squirtle overall, they still had 1 or 2 important battles where they could shine. Charmander has an advantage against Erika at least. Pikachu could be good against Misty and Lorelei. In the case of the Chikorita line every major battle either has no direct type advantage or it has a distinct type disadvantage. There is no scenario in the Johto region where having a Meganium is better than having a Feraligatr or a Typhlosion, not even briefly. I can't think of another game that did something like this to a starter.
Even if Meganium had not been so unlucky and was introduced in another region where there are more advantages to using a grass type, it's still a really forgettable Pokémon. It's not fast and doesn't have attacking power. It's supposed to be a wall, but again, the mono grass typing gives it way too many weaknesses for that purpose.
Since it was a remake i thought Chikorita would have seen more improvements than it did. In Frlg Charmander learned the steel move metal claw to help it out against Brock's rock type Pokemon. Also the gen 1 mechanics of special attack and special defense being one stat were gone, so Charizard had a good special attack that was over 20 points higher than before. In Oras Sceptile got a mega evolution that had a dragon dual typing. Blaziken even before the Mega Evolution, got a great hidden ability, speed boost.
The other Johto starters kept improving with time too, but by contrast Meganium seems largely unchanged. The only attacking moves that it learns by level up are grass and normal type even now I think.
I grimly marched on to beat the game with Meganium in the party purely out of sentimentality. Had it not been my starter it would have been boxed almost immediately. However, it was not helpful in these battles, beyond easing my conscience, and another Pokemon would have to usually be sent in to salvage the match whenever I tried to use Meganium. Ampharos was essentially operating as my starter Pokemon in Soul Silver.
As soon as I struggled and flailed my way through the elite four I retired Meganium to the PC. I had technically completed the game without abandoning my starter. It was time to pass the torch and let another Pokemon have this spot. As far as I was concerned our contract was fulfilled now. No need to punish myself further by using Meganium to fight Red in the post game, conquer the battle frontier with it, or rematch all the same Johto gym leaders and Elite four members this Pokemon previously struggled against with their full, new and improved high level teams.
When Pokémon Crystal rolled around on the virtual console, I chose Totodile, and it performed very well, and I was happy. When I first played Pokemon Gold I chose Cyndaquil, we breezed through it, no problems. I would use either one of them again replaying Johto, but not Chikorita. Sorry.