Did you forget to complete your post or have you only played 2 pokemon games?

Just curious, did you guys play Diamond/Pearl, or Platinum?

Those are the only games I've played recently enough to judge, also the only ones I finished. But I did play Diamond, Platinum, and Soul Silver as a kid, never got far in them though and never finished them. 

As a matter of fact, yes.

My rankings:
Great Games
1) Genneration 4: Platinum is still the GOAT Pokemon game. Greatly designed region, great set of new pokemon, the new wi-fi functionality, physical/special split introduced. Fixed the two biggest flaws of D/P, the slow speed and the weak regional pokedex. HGSS are great remakes as well.

2) Generation 5: Recently replaying it, I really appreciate it after the constan gen 1 pandering Game Freak does now. Black 1 felt fresh with all-new pokemon (even if the designs were somwhat hit or miss), and with the best story in any pokemon game, and the New York based region. Then Black 2 follows it up with an expanded region, and the Pokemon World Tournament. B2/W2 is second best game in the series behind Platinum. Used to hate these games, but really appreciate them now. Best music too.

3) Generation 3: Solid games as well. Hoenn is a very diverse and varied region, great set of pokemon. Not much else I have to say. FR/LG are great too

4) Generation 7: Good games as well. I used to rank it no.2, but recently playing I'm starting to see some of it's flaws. Still, getting of HM's, incorporating the pokemon anime style and more lifelike proportions in the world. shaking up the formula with trials (which didnt work out too well, but the final totem fights were great), regional pokemon forms, Ultra Beasts, etc. Region felt more alive, with much more pokemon in the overworld, and trainers models in pokemon battles, not just illustrations. Admittedly festival plaza sucked, and the replacing DexNav with rotom dex sucked.

Okay tier:
5) Gen 2: It simply didnt age that well. It brought a lot of new stuff to the series, breeding, dark/steel types, held items, etc, but it's simply outdated now.
6) Gen 1: Same as above, really.

Dumster Fire tier
7) Generation 6: I don't know where start. X/Y is truly horrible. That chibi artstyle, piss easy difficulty, megas that were poorly executed in-game, the worst blandest region in any pokemon game, worst evil team, worst "rivals" forgettable music, only 70 new pokemon (with many pokemon being underwhelming/hideous designs).Saving grace being PSS. OR/AS is good, but with how bad X/Y is, it's easily at the bottom.

For the seperate categories
Art Style:
Gen 5 > Gen 4 > Gen 7 > Gen 3 > Gen 1/Gen 2 >>>>>>>>>>>>>>>> Gen 6
Soundtrack:
Gen 5 > Gen 4 = Gen 7 > Gen 3 > Gen 2 = Gen 1 >>>>>>>>>>Gen 6
Region:
Gen 4 > Gen 5 > Gen 7 > Gen 3 > Gen 1 = Gen 2 >>>>>>>>>>>Gen 6
New Pokemon:
Gen 7 > Gen 4 > Gen 3 > Gen 2 > Gen 1 =Gen 5 = Gen 6
Story:
Gen 5 > All others > Gen 6

Yea, only D/P never really gave a shot to Platinum, D/P left me that sort of sore spot.

In that case, I would really reccomend giving a second chance to Platinum. It fixes the issues and improves on Diamond/Pearl. Most notably, the game speed is significantly increased.

Uhh.. I haven't played SoulSilver in a while so I don't recall too well..

But I think they were both about the same. If you found SS slow you will probably find Platinum slow too, unfortunately.

High tier
1. Pokémon Let’s Go
2. Pokémon Blue/Red
3. Pokémon Snap

Medium Tier
4. pokémon Black and White

Low Tier
5. Pokémon Black and White 2
6. Pokémon X and Y

Haven’t played any others.

BW2=HGSS>rest
However, I realized the difficulty start to drop on XY, but since, i addapted my playstyle, and started building multiple (underleveled) teams, and I started enjoying the games more, knowing better more and more pokemon, strategies, team combinations.
So, I can say I had a really good time with XY, ORAS, SM and even lets go. More than the first 3 gens.