My problem right now with Ralts as an S Tier Pokémon is that, so far, I would rather use Torchic than it, and Ralts faces significant issues that I mentioned in my previous post: it's frail and can't really sweep properly. You're right that I wanted to compare it with Alakazam (and with Grumpig too, this answers your question
Volt-Ikazuchi on why I have three Psychics in the same team) but I think that if you look at the screenshots, the problem is not necessarily the comparison with Alakazam (which so far has filled the description of an S Tier very well) but to other teammates, and I put in question if we can really call S Tier a Pokémon that takes so much time to become good.
Just wondering, who gets Shock Wave in that scenario? Ralts wants it to not be walled by Dark-types, but it can live without it with the right teammates. Alakazam and Spoink absolutely need it no matter what or else they have no coverage.
Your testing also has the issue of being *very* inorganic. People don't usually split Exp by giving mons set amounts. They usually level mons evenly.
For example, If I'm up against Brawly with a Ralts at Lv. 13, it's grind or bench time, especially with other mons at 3 or 4 levels higher.
Slow Exp. means it'll usually drag the team levels down, so for example, you got 8.179 total exp in those Pre-Slateport Brawly screenshots. You'd be with all mons around Lv. 14~15 instead of 2 at 16 and Ralts at 13.
As for Ralts' true position... It's really a rare case of an S- mon, but we don't have that tier, so let's list the pros and cons.
Pros
Excellent stats.
125 SpA hits hard even through resists, 115 SpD allows it to tank dangerous special attacks from the likes of Tate&Liza, Wallace, Drake, and Glacia. 80 Spe is adequate and with natural Speed EVs from beating in-game trainers, which will have plenty due to positive matchups against Flying-type mons with its Electric coverage, it can outspeed basically everything but the fastest mons in the game.
Cost-Efficient and Versatile.
Kirlia learns both Psychic and Calm Mind at an incredibly low level. This means it doesn't need to worry about lackluster STAB or needing a Game Corner TM. In terms of coverage, it wants either Thief (which also has excellent utility against Leaders by stealing their Sitrus Berries) or Shock Wave. I'll get back to Shock Wave in a second. Then, it can get the free Thunderbolt TM from the New Mauville quest or buy one at the GC, but if it has Shock Wave, it can hold on to that if you need the money for other TMs.
Its 4th slot is extremely versatile. Keeping Thief allows it to steal Sitrus Berries from Leaders to heal damage taken while setting up Calm Mind, this is most important during the Kirlia phase. As a Gardevoir, it can upgrade to using Reflect/Light Screen, with Reflect being the better option to patch its Defense and allow easier setting up if necessary.
However... Keeping Shock Wave allows it to be the absolute best counter to Juan's Kingdra. It can Calm Mind while Kingdra tries to Double Team, and then slam it hard with Shock Waves it can't avoid. Other Psychics can do it, but they'd need both the CM and Shock Wave TMs. Hypnosis also becomes an option Late-Game.
Versatile Matchups.
Gardevoir has several good matchups where it can both contribute or outright sweep, with many of them being difficult such as Winona, Tate and Liza, Juan, and Wallace. It can outright sweep three of those, and setting up screens on Tate and Liza makes it a much easier battle.
Gardevoir will generally perform best as a strong glue that handles problematic sections and matchups. With Calm Mind, even would-be checks are just outmuscled after even just one boost due to its stellar SpA. It also destroys most route trainers with ease.
Cons
Slow Exp. Group.
This is the one nagging problem that will haunt Gardevoir the whole game. It will drag its team down Exp. wise and there's really no other way to say it.
Lackluster Ralts Phase.
Ralts is a weak Pokémon. Straight up. Unlike the likes of Magikarp and Abra however, it can pull its weight when it comes to Route Clearing. Poochyena will be a problem because it can't hit them with Confusion. But otherwise, it can do just fine.
When it comes to matchups during that period, Ralts will be best used at softening leaders by beating down their weaker mons allowing one of your better options to cover their ace, or taking down their aces with its teammates taking care of the weaker mons so it can come in unscathed. You will need to know what you're doing for those tho.
Common Misconceptions.
Early Gym Matchups.
Roxanne's Geodude isn't too much of a problem to it. Nosepass is a bit too resilient and honestly hits too hard for it to be a *good* matchup. One Double Team (Just one!) already makes Rock Tomb much less of a concern and you literally won't have other moves to use anyway. For those like me that don't like cheese, Growl is also an option. A sweep is nigh-impossible though.
Brawly requires Ralts to be able to tank a Vital Throw, which likely means going to Slateport first. This isn't too bad. Ideally, you'll want to get the Thief TM there so you can steal his Sitrus Berry. The plan is simple. Growl until it uses Vital Throw. A -1 VT is easily survivable.
Use Thief, heal up with the Sitrus, 2HKO back with Confusion before it can 2HKO you. No sweat. Very few things can just handle Brawly's Makuhita that easily.
Wattson is an RNG fiesta where no one sweeps. Between TWave and Exploding mons, it just won't happen. It can beat Manectric with Thief and Calm Mind strats. I recommend giving it a Cheri Berry for the inevitable TWave. This guarantees a CM, and allows you to steal the Sitrus at your leisure. Kirlia can and will beat Manectric one-on-one and it's one of the best options against Magneton because it can CM and scrap with it. Most mons can't even attempt to do so.
Flannery is also a good matchup to just try and steal stuff, namely Torkoal's White Herb, making Overheat much less of a threat, especially since you might be able to sneak in a CM against one of her other mons. Possible to sweep. Body Slam might be a bit troublesome tho.
Norman is a complex one. If you have Gardevoir, you have a very hard hitter to scrap with him. If you have Kirlia, things get much trickier. Anything with low defense has an outright bad matchup against Norman, Kirlia might not be an exception, though it does fare better than most by having a very strong STAB. It might be able to deal with Linoone or Vigoroth. Wouldn't count on either. This is Ralts' worst matchup in the entire game.
After that, you will have evolved Kirlia and will have an advantage or defensive utility over pretty much anything not named Phoebe. Enjoy winning.
Kirlia Phase
Kirlia may have weak stats, but it does have excellent moves at its disposal. Getting off even one or two Calm Minds allows it to muscle past dangerous special threats that would be troublesome for many other mons.
It can't be understated how impactful early Psychic is. You'll have most of your teammates fumbling around with 60~70BP STAB options at best, and Kirlia can even boost it with one of the best setup moves in the game.
With all of that said, I personally believe Ralts should be kept at S, but would understand, despite disagreeing with it, if it's knocked down to a because of the combination of the Ralts Phase and Slow Exp. Group.