Medkit self healing should be 32 seconds, so it’s not more efficient than altruistic healing.

Personally, I think the most recent changes are fine. Though medkits are still a little more efficient, that's the benefit of bringing one. Using a medkit saves 8 man-seconds on one heal, maybe two with add-ons. Consider it's opportunity cost: instead of a medkit, you could bring a toolbox, which easily saves more than 8 man-seconds on a generator. Or, you could bring a flashlight, which could help with a game-changing flashlight save or allow you to sneak past a blinded killer in chase.

Medkits before were way too strong when a survivor could heal himself two or three times in under 16 seconds. Now, I think they'll find a comfy spot with balance taken into consideration.

You're discounting several things to make this argument. You say it takes 3 survivors 12 seconds to reset, which lacks a lot of nuance. For one, it requires all three survivors to first run to the same location, which takes time. Also, you neglect the amount of time it takes to set up the boon (14 seconds booning + 40 minutes finding a dull totem). To be conservative, we really should double the time you say: 24 seconds for 3 survivors to reset. 12 seconds spent running to each other, 12 seconds spent healing. Even still, we are neglecting the time it takes for survivors to run back to whatever they were doing after healing, but we will ignore that for now.

Making 3 survivors take 24 seconds is the equivalent of 72 man-seconds. That's almost a full generator, spent on healing. Meanwhile, your gens are regressing, you've kicked some pallets, & you're almost certainly chasing the last survivor or have their hook timer ticking down. If not, then you can always walk over to the 75% of the team healing and interrupt, applying pressure to all but one survivor, forcing either a down on one survivor who was yet to full heal, or causing other survivors to take hits & waste all that time running and healing.

Oh, now we have to take in count all of those things? It is not simply "altruistic should be lower because self healing make us waste the double of the time amount healing because my favorite streamer said so" and the point is made? Now we have to take in count walking times, finding another person to do the healing and real scenarios instead of just the mathematical theory?

Anyway, to answer your points: Perks or map to see totem auras and now CoH would show the auras of the injured survivor inside of it. Taking in count the 14 seconds of booning should not be necessary because the survivor bringing it would bless a totem with it whatever someone need healing or not and in any case that time spent blessing is "paid" with time lost doing other things like repairing gens, so is not related to the healing itself. But even forgetting that and taking it in count you would only have lost 2 seconds for those 3 heals (3 x 8 = 24 seconds without boon, 3 x 4 = 12 with boon, 12 + 14 = 26 taking in count booning, 24 - 26 = -2 seconds lost) in exchange for the next to be faster, so if the killer doesn't snuff it that 14 seconds would not only pay themselves, they would make profits. And if a survivor was injured he most than probably was running in front of the killer and doing anything else before being injured, so I don't think they would come back to that after healing. Not that SWF would have any of those problems like I said, as they just need for the killer to be chasing their looper, coordinate and go to the CoH range to reset all the pressure. Then, try to change the killer target, heal the other, and repeat.

Making 3 survivors take 24 seconds are not 72 because two survivors heal at 2 c/s, so each survivor would take 12 seconds making it 36 seconds. And they could just maintained the 24 seconds base and just give the buff to CoH, making altruistic 12 seconds and with 2 healers, 6 seconds, and made the medkits go from 50% speed (1.5 c/s = 16) to 100% (2 c/s = 12 seconds) and not only make to even try to bring a rare medkit worth it but it would have the same effect, as now doing altruistic with the best medkit would give you a healthy survivor in 12 seconds and 20.4 charges in a gen in the other 12, making it a better option than making that other survivor self heal with the medkit by simply dropping it (something that people seems to conveniently forget you can do).

But the new change wasn't because altruistic really needed to be lower, or the new base healing was wrong in any way, or altruistic wasn't a problem before. They made the new changes because of the crying, because the fog forbid they nerf the survivors without them having a tantrum and review bombing the game, so papa BHVR would give them a candy so they shut up. And that's it.