Some say it's the new designs looking lazy and others say the formula has become too familiar -I have a complaint not many people tend to address and what I believe is why some people cannot stand the newer Pokemon designs. For me, the biggest problem with Pokemon is the completely different art style it has now from then. 

I don't like how his style is is less detailed and more... round nowadays XD I miss the old Akira Toriyama inspired look the first 2 gens had. That's my biggest complaint about the series over the years. The new art makes some Pokemon like Bewear look flat because they rely on the shading to make it look 3D but it doesn't x.x 

Maybe I'm just crazy but that's my weird complaint. Here's a few more comparisons:

Gen 1: 

Gen 2:

Gen 3:

Gen 4:

Gen 5:

Gen 6:

Gen 7:

FINALLY, somebody who agrees with me!
I made a thread about it back when ORAS were announced but people for the most part (not all of them) didn't agree. I really don't like the way the series has been going in terms of design.

Didn't know if I would agree or not when I read the OP but then I saw this:

Of course, holy shit Scyther looks badass but more importantly, this perfectly encapsulates everything you need to know about Scyther.  It's something a lot of the new art misses.

While we're on the old Pokemon vs. new Pokemon, am I the only person that thinks many of the early gen Pokemon were poorly transitioned into 3D?

There's an app called Pokedex 3D pro. It has every pokemon(besides gen 6 and 7) in a beautiful 3D model. Here, let me show you an example.

Pokedex 3D pro:

Pokemon XY/ORAS:

Perhaps it's the way they made the models which makes a lot of the pokemon look weird? Personally, I think that the models used in the Pokedex app were phenominal. It could have easily been the 3DS's weak hardware which caused them to use different models

Gotta agree. I really dislike the turn on design the series got since gens 1-2. For the most part it seems to have gotten worse and/or simplistic. Furthermore I really dislike how there's way too many useless pokemon that not only have poor design but have zero impact wether you are playing offline or online/competitive. Take Volbeat, Pachirisu, Durnsparce and luvdisc as example. They are utter rubbish. For every 150 new pokemon half of them are useless.

But, many of the gen 1/2 pokemon are useless as well.

Also, pachirisu was actually a key pokemon in the video game championship last year. You should look yourself. It was very interesting.

Edit: nvm!!!!

Interestingly around Gen 3 they 180'd and gave everything pointy bits and armor.

What is happening to Pokemon is happening to allll Japanese games - Overindulgence in Anime garbage. Pokemon feel less like that words animals like in gen1/2 and more like ... Digimon. C'mon, Lucario looks like a Digimon.

Funny, it wasn't until Gen4 that the quality of the artstyle became acceptable enough for me to get into Pokemon. Anyway, Pokemon was never just one style, every gen has all different types of Pokemon, from detailed high concept mons to simple soft rounded mons. I say what matters most is variety, and Pokemon has plenty of that.