A lot of people like to praise generation 1 for having great Pokémon designs, and while I really like some of the designs (such as Lapras, Bulbasaur and Eevee), I think it was overall the worst generation in that regard. Not only design-wise, but they also made some decisions (due to hardware issues or simply lack of identity) that don't fit anymore with what the series has become. Here are some examples:

1. Ekans is just a snake. No more, no less. Its name is also just "snake" backwards.
2. Nidoran Male and Female are two different species. I guess the Game Boy couldn't handle sprite differences based on gender.
3. Nidorina and Nidoqueen can't breed. Both Nidoran, Nidorino, and Nidoking can. That's still true in newer games, despite it making absolutely no sense at all.
4. Dugtrio is the laziest Pokémon ever created. It literally is three Digletts together, not a single new feature added to it. I can understand Magneton being three Magnemites together because that's what magnets do, but moles don't do that as far as I'm concerned.
5. Psyduck and Golduck are pure Water-types, despite Psyduck literally being an amalgamation of "Psychic" and "Duck". 
6. A lot of Pokémon are literally wearing clothes. It's not like they have clothes-like aspects, they're clearly using human clothes. Jynx, Hitmonchan, Mr. Mime, Machoke and Machamp all wear human clothes.
7. Kadabra and Alakazam are holding spoons all the time. Kanto must have a pretty big spoon factory. It's not like the spoons are part of the Pokémon either, they're clearly just holding them.
8. Graveler evolving into Golem makes no sense. Graveler is a living rock. Golem is a reptile "stuck" inside a rock.
9. Seel is just a seal. They just changed a letter.
10. Dewgong is just a Dugong. They just changed two letters.
11. Muk is just a larger Grimer. And they're both just boring piles of mud.
12. Krabby is just a Crab. Its name in Japanese is literally "Crab". The only inspiration for its design is a crab.
13. Electrode is a terrible evolution. It would have been much more interesting to go from Voltorb (a Poké Ball), to a Great Ball and then to an Ultra Ball. Instead, they just flipped it around and gave it a mouth.
14. Mr. Mime and Jynx look too much like humans. It's weird to even call them Pokémon.
15. Venomoth is just a regular moth. So creative.
16. Exeggcute is a bunch of eggs. Just eggs with faces.
17. Kangaskhan is born with a baby in its pouch. I guess they didn't think that through.
18. Goldeen is just a goldfish. There's absolutely nothing interesting about it.
19. Dragonair and Dragonite don't even look remotely similar. Why are they part of the same evolutionary family?

1. Gen 6
2. Gen 3
3. Gen 7
4. Gen 4
5. Gen 2
6. Gen 5
7. Gen 1

It's because you're too young.

I like pretty much all of them, *some* of the alolan forms made them worse though.

Gen 5 still has the worst in my opinion, I mean especially when half the dex was set to emulate the original pokemon. 

Still every generation has it's own fair share of great and not as great designs.

Gen 2 was definitely worse.

And it's Gen 1 what do you expect?

That's a tough battle...

At least Golduck should be a Psychic type. Its name is Golduck even in Japan, with the Gold part symbolizing Psychic powers, not the color. It also has a gem on its forehead, usually associated with Psychic powers.

Yeah, I forgot about Gyarados' typing. It should either be pure Water or Water/Dragon.

Or maybe it's because I'm not taking nostalgia into consideration.

Oh, god, don't even remind me of Alolan Persian and Dugtrio...

My problem with Gen 5 is it trying to emulate Gen 1, but I think the designs are better overall.

People really do not like things that are popular don't you know. However if we are talking worse, Gen 5 and 4 take the cake for me. Gen 6 was a breath of fresh air. 

I'd probably say Gen 6 is my favourite design-wise.

I disagree. Recent Pokémon generations had much better simplistic designs. Just look at Rockruff, Skiddo, Pyroar, Rowlet, Helioptile, etc.

It's a tough battle tbh

Exactly. I'm not saying it was bad for its time, I'm just saying why I think it's the worst one considering the whole series.

lol no

Gen 5 was easily regarded as the worst gen for pokemon designs. 6 and 7 they stopped adding so much which helped, but gen 1 is iconic.

3 and 4 were ok overall.

1 and 2 had the best pokemon designs