Tanning is too strong.

I agree, I wish there were different levels of tanning. For example, if you only sunbathe for an hour, you just get a very light tan. But if you sunbathe for 5 hours, you get a dark tan. The Sims 4 tanning is too much.
They could potentially update this, and they should be able to, since we did get that 100+ skin tone update, but we'll see if they do...

There's also a mod that has to do with skin tanning and sunburn, where your sim gets sun exposure whenever they're outside in sunny weather, and can even have skin problems because of it. But I don't know if they're still updating it; Iron Seagull did a video on it a couple years ago.

Tanning does need to be toned down, especially with the time it takes to get one in TS4 and the result you get is far too strong.
They should keep it to a simple holiday tan.

If we consider current result 100%
I'd say 50-70% would be fine, perhaps with some randomization or two stages. I'd also like it if it took a bit longer to get. If they could do a gradual system I'd be overjoyed.

I also wouldn't mind it too much if sims got get tans outside of deliberately sunbathing to make it more meaningful to their look and what they've been wearing when they get it. Don't make a sim get it no matter what just because they've went out but maybe if they've been out for quite a while on a particularly sunny day.

honestly as a player i think its pretty normal

For me it's completely NOT normal... there should be stages of tan and not just one simple tan and with that, the effect would be much better. I like the new system with patterns from clothing, but I feel like there should be an improvement of this system to also introduce tanning whenever you are in the sun and not just when you lie on the sunbed and like I previously stated, tanning behaviour of different skin colours... good that we have flerb, but something like this SHOULD be made by EA

I disagree about tanning while in the sun. I like that it is optional because I never want to see a tan on my perfect sims. I would be mad if they forced it on my sims. Many live in sulani so they would all be automatically tanned.
Based on this pic it seems a bit strong. But I don't know if toning it down is the best option. Then tanning gets nerfed and people complain sims can't get tan enough. Would be nice if they could add stages yes. But that's just adding more complexity people will soon complain is broken. ?‍♀️

REMOVED BECAUSE OF EA

I totally agree. With some skintones it works kind of okay but if you have a sim with a light brown color that sim will become so dark they look like a different race.
It really depends on the skintone but I agree with you 70% of the time the result in my game is too extreme, still realistic, but too extreme.

The trouble a lot of pale skinned people like me have that they never go brown. They just go red and burn and don't suntan at all. That should be in the game to be really realistic.

That's why there are so many tanning parlours in the UK. Tans have to be sprayed on and many overdo it! ;)

But I have to say, that tanning shown in the OPs first post, might be a bit extreme but it is absolutely possible! Though it doesn't happen like that in just a few hours, I have seen people (including myself) getting incredibly darker after long exposure to the sunlight. I lived in Greece as a kid and the sun shines there the whole summer long, after 4-6 weeks of daily exposure you do end up looking like you changed ethnicity.

Like the rest of the we only care about dark skin tone update the tans seem to be made for the darker skin tones and the lighter skin tones get what they get without any thought put into it.