It's just human nature for when set or collection is presented to judge and rank them amongst each other, even if the lowest rung is still the bronze medalist at the Olympics. I don't think any single generation or main series game is really hated on collective, but since negative voices ring the loudest it's easy to get the wrong impression.
Now enough of that sweet stuff, it's time to get salty. Because I ordered a plate of level design and Sinnoh gave me nothing but beef!
For this to be a fair comparison, I'm choosing Platinum versus HG/SS because G/S versus D/P will just confuse the issue with software limitations and design bugs that were later corrected. Now, I will preface this with admitting that HG/SS is my favorite but I do agree with Pika Pal's statements. I found the game fun and challenging, but if you say that the challenge was completely artificial and due to lacking elements then yeah, I can't deny that. I also agree that Platinum overall is still a pretty good game, and that the trainers and bosses managed to be challenging but fair for the most part.
But that is just one half of the game's world, and for me all of Sinnoh failed hardcore on level design, almost to worst of the series. Sinnoh is linear, there's only one path from start to Elite Four, but you'd never really notice with how kooky crazy that path is, having you double back, reroute, and get flung to and fro around the map like it's little sock puppet. Yet despite all this you still hit road blocks, both of the HM-variety (gotta get surf to go to Canclave!) and the "can't go here yet" obnoxious ones (Psyduck's gotta headache and you gotta wait). So the worst of linear design and the worst of non-linear design, both melded together. How do you even do that?!
But that's all overall impressions. I just wish there was one solid route to really illustrate my point...
Ladies and Gentleman, I present
The Snowpoint Trail.
The path to Snowpoint contains every single reason I think Sinnoh's level design is poopy. All rolled up into a grim trek north that ends with you frozen in a snowbank considering what Bibarel tastes like as you shiver in the cold. Did any of the designers ever hear of
the Donner Party?!
1. You start at Mt. Coronet. Wow, stumble right out of the gate. The designer of Mt. Coronet went to the same school as the Ocean Palace of Phantom Hourglass in
Ways to make a bad level: 101, make you repeat it over and over in bigger chunks. So in this one you've got to grab 2 or 3 HM Slaves and bench some fightin' mons just to move some rocks out of your way. Yay? This is why the HM policy got nuked in Gen 5, Mt. Coronet requires 7 moves total to fully complete. Luckily you don't need all of them at this moment, but just you wait. Just you wait.
2. No Fly spots. So instead of a bottleneck, we are now stuck in a corridor. There's no getting off the Snowpoint Trail until either finishing or starting over from the beginning. True, at least the trainers won't reset but you will be stuck with the HM slaves needed for Mt. Coronet until the end of the trip. They were nice enough to give you a resting spot half-way, but no such luck if you run out of items.
3. It's LONG. It's technically two routes, 216 and 217 but since they just flow into one another it's really one long super route. Saving grace is that wild pokemon only pop up in tall grass, and there isn't much of that. So you don't need that many Repels the further you go (which is good, since the inventory system in Gen4 was... bloated).
4. The weather. You are dealing with hail from start to finish, which means that no matter how good you are, your pokemon are fighting a war of attrition against hail damage and trainer damage. So even your best mons get whittled away bit by bit. Only one type of pokemon is immune. To add insult to injury, it even effects the player, YOU! Visibility starts at a premium and then lows to a hair above "Flash cave" level as the snowstorm gets worse and worse as you go north. So it's like a Fog route, but Defog won't work. Why did we ever need Defog, other than for Gen 6 battle mechanics?
5. The trainers. Due to Sinnoh's trainer classes, 60% of the trainers on this route are Ace Trainers. Only about 20% are actually the ice using skiers and snowboarders, the remaining are Ninja boys (popping out of the snow. LIKE DAISIES!) and Karate guys. While this could be a legit and fun challenge, Ace Trainers use a diverse set of pokemon and have a tiny bit better A.I., all the other flaws make this one a flaw by association. It's unfair to take on diverse trainers when half your team is an HM slave and the other half is dying to hail. So you can't cheese the route by spamming Close Combat until your girlfriend says "I need some space." You need to meet diversity with diversity... and your underleveled Bibarel who just sticks around for Strength and Rock Smash.
6. Gee, Mr. Stage7-4, that all sounds pretty bad but not worth ranting over. I feel this garbage pie is just missing something to take it into the WORST LEVEL EVER territory. Something super annoying, adding nothing to the game but to watch you suffer and suffer and suffer and suffer
THOSE STUPID SNOW PILES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The closer you get to Snowpoint the more you have to deal with snowbanks, areas of the map that reduce your walking speed to a crawl and sometimes trap you, making you shake yourself out of it. And they are everywhere! And unlike the Great Marsh and the swamps, there's no trick and no visual clue, any part of the snow can do this and at some places it's just unavoidable. You cannot just dodge trainers running through the map as fast as you can to get this whole ordeal over with. And it never lets up EVER. Even after you get to Snowpoint there are still these snow banks to trap you and waste your time. Who in there right mind came up with this?! HOW IS THIS FUN?!!?!?!?!?!?!?!?!?!?!?!?!(death by punctuation)
And every other level in Sinnoh just takes one or more of the above points and runs with it, especially HM abuse. Sinnoh's level design really is the worst in the series, both before and since. I love open ended and complex design, and I find linearity without a point annoying, but this just sucks all of the fun out of exploring a world. That's why I think HG/SS is superior to Platinum. Sure, most of the routes were short, but all the annoying parts were side dungeons that you only put yourself through because you wanted to, not because you had to. And it added some true freedom, even if in just a small dose, allowing you to do gyms 5, 6, and 7 (and almost all of Kanto) in the order you wanted.
The icing (snow pun) on the cake is that when you get to Snowpoint, there's a ferry dock. Sure, it doesn't go back to the mainland, but it's almost like the Snowpoint citizens are saying "Wait, you WALKED here? Nobody does that, we all take the boat!"