Can I hate all three? I mean, WTF is this!? Each Generation has one I like based off looks alone. Before playing I tend to look at final evolutions to see which looks the best. Let's face it, any starter can get you through the games with minimal/no help. I mean I even played Gen I picking Charmander and beat the first two gyms, (and the rest), with him alone. Elite Four? How about Epic Charizard?
As of right now, I feel this is probably the weakest Gen for starters. Not a single one I like. I will have to see their final evolutions.
I see this every generation. Some people will always hate all the pokemon in the beginning. If we're going to submit the weakest starter trio based on first stages designs alone, I'd submit the bland and mostly not very colorful Kalos starter trio. I like them all, but they just aren't as appealing as some of the other starters.
Honestly, even though by looks they aren't my favorite, I think these are the most thought out starters in existence, with each one being based on a real animal that's also endangered.
Rowlet isn't the most colorful grass-type ever, but he has a pleasing, round appearance fitting of a young, first stage pokemon. He also has grass elements: his bowtie and the leaffeathers on his wings. He also has the cute quirk of turning his head around to receive orders in battle, and sending leaves hurtling forward when he swipes his wing.
Litten is currently my least favorite, but he has a simple yet creative design that somehow comes off as bright and colorful even though the majority of his fur is black. At first I didn't like the fur tufts on his face, but his design would be a lot blander without them. He also has a quirk that seems almost obvious and brings up many cute scenarios - his furballs that light on fire.
Popplio was my least favorite to start with, but now he's grown on me with his bright colors and body shape that is somehow sleek and clumsy/dorky at the same time. His party hat nose is nice looking also, at the additional artwork for him gives off the idea of a fun, quirky pokemon who loves to clown around and playfully show off.
Sorry for the length, but I'm getting sick with people trashing them and I just had to defend them.