Seconding on Sinnoh game.
Kirlia really got hit hard by making its crucial move learnt later (Calm Mind from L21 to L25, Psychic from L26 to L31), which made Pre-Gardevoir phase awful, not to mentioned, Ralts was also horrible on routes, i had mine somehow struggling to 1v1 a Machop. As Gardevoir, 80 Speed felt middling in this game.
This is also the game where i had high expectation for Kadabra being as good as in other game, but it ended up performing mediocre overall (more like a C Tier mon if you ask me), both the wild one and Kazza. Here's my Kadabra experience during the test run in Platinum, both wild and Kazza, and i don't know if i would blame the game's difficulty here:
Gardenia - Really needs Psybeam, you don't sweep with Confusion (you only beat Turtwig and Roserade)
Fantina - Shadow Sneak and Sucker Punch can be annoying.
Maylene - can't reliably sweep a Fighting Gym Leader unlike Torterra or Gliscor, Meditite dealt half HP with Fake Out, so not even Inner Focus may save you here. You only 2HKO Lucario while it shreds you if Meditite went for Fake out (Kazza gets outsped by Lucario)
Wake - Kazza has a roll to 1HKO Gyarados with Specs Shock Wave thanks to +SpA Nature
Byron - only beats Magneton
Candice - Borderline F Tier, everyone one shots you, and Kadabra doesn't one shot back with Specs Psychic(You need Specs Grass Knot to 1HKO Piloswine)
Cyrus (HQ) - F Tier. Crobat one shots you unless you have super high HP and Def IVs or something
Cyrus (Distortion) - same as above, Crobat likely demolishes you. Kazza can 1HKO Gyarados with Specs Shock Wave thanks to +SpA Nature tho
Volkner - F Tier, Kadabra doesn't one shot anything and gets one shotted back (Jolteon is faster, Kazza gets outsped by Raichu and Electivire)
Aaron - Beats Yanmega and Heracross, and that's it
Bertha - Good, but you can't reliably deal with Whiscash, it lives a hit and had a chance to one shot you back, and even if you lived a hit, Hippowdon comes in next
Flint - F Tier, everyone one shots you and you don't 1HKO back (Infernape is faster)
Lucian - Even with Specs Shadow Ball, you only beat Mr. Mime and still loses against the rest. (Kazza gets outsped and may run into issue like fast Light Screen)
Cynthia - its Cynthia, but i like to mention Kazza gets outsped and 1HKO'd by Roserade unlike the wild one.
In other games, Abra joins with some sort of conviniency, GSC has Abra join at the point where you can buy elemental punches, RSE has EXP Share instantly available if you backtrack, FRLG had Abra joined at like L13, and there's like Thief TM nearby(which is special in that game), HGSS has Abra joined at L15, which is one level away from evolving. In DPP? technically. The earliest wild Abra joins at L4-5, which is lower than RSE, and you don't get EXP Share at that point until Gym2. While DP has Hidden Power at that point, Platinum isn't and it was absolutely a painful experience. Yeah, Kazza exist, but it had 2 issue;
1. obedience. Kazza will stay disobedient until after Gym 2, and it doesn't stop there, the obedient cap is now L30 until after Maylene, so you have to be careful.
2. Nature. Kazza is locked to Quiet, and while the +SpA is great, the reduced Speed nature really hampered it in some fight
Fantina pulling up with Shadow Ball Mismagius and Jupiter snatching souls with Skuntank might have closed the book on Abra's dominance, but I'd have to run some tests.
Kadabra/Alakazam can beat Skuntank with Substitute, Disable, Miracle Eye, Psybeam, though that's super gimmicky, i know. And speaking of, I wonder if Kadabra/Alakazam can potentially 1v1 Fantina's Mismagius with Sub + Disable? (I haven't actually done it myself during my test run, Kazza as Kadabra gets outsped by Mismagius tho, unsure from Kazza as Zam)