PHI or (potentially) SPI are the strongest traits in terms of magnitude. They are also directly influenced by difficulty as this drives a lot of the
value of bulbs and assistance in diplomacy navigation way up. SPI is really hard to quantify as the strongest aspect of it *is* diplomacy; anarchy turns are pretty trivial in nearly every game I've ever played and you can plan around them, bypass them, etc. And no I still don't think SPI is all that great, I never really have. But in terms of what it can do, greasing diplomacy at a key point can be a hinge for the entire game. Or not, depending on the map or opponent field, random religion aligning, etc.. It's hit or miss, but with undeniable potential in the right situation, or perhaps just a slight advantage here or there, convenience of having some freedom with civics etc.
FIN /CRE are excellent ease of use traits. Each just enhances already standard play further and makes things that much easier for you. Cherry on top kinda stuff. They aren't as involved as the micromanagement inherent with SPI or PHI to min/max things, and not as specific in how to utilize it (fail-gold) like IND, yet they can still be abused hard if you want. I don't think of either as a power trait like PHI but games are certainly simpler with either trait giving one just a little bit easier of a time.
IND is....I'm unsure anymore. I certainly would rather take CRE than IND these days. Fail-gold help is excellent, but I pretty much stopped doing fast MC stuff and dislike early wonder gambits (sans Mids or GLH on the right map) when I started to move up with the help of the NC games so the cheap forges seems like a more specialized gambit than really helpful in a general sense ( I'll just eventually 3-pop whip them later anyway) while I've learned to either build wonders without IND or how to forgo them altogether if not a feasible choice. And a lot of times, I find myself in conflict between trying to balance out funding more immediate expansion with Build Wealth and investing meaningful amounts of fail-gold for better research slightly later. Trying to fit in running specialists puts on even more strain economically when those pop slots can't work a tile. Overall I think it just mostly enhances something I'll do anyway (fail0gold) if I have a resource to abuse, but I can mostly get along without it. I've never felt broken in a tough spot by not having IND, though it certainly feels great when you're doing well in a game and can afford to invest fail-gold at will.
ORG/CHA I feel are sorta similar to FIN/CRE as ease of use traits, just a little bit weaker and with different methods of application. ORG is a personal favorite trait, it lets one expand heavier (which I do a LOT, and because I can, not being a Deity player gives me a chance to snag too much land

) and makes Lighthouses trivial buildings for any coastal spot (great for working coast when you have to...such as when overexpanded), and eventually Courthouses become a good thing to have since they are cheapened to Granary cost. CHA means a LOT when squeezed for happiness, which on a rough map can last for a LOOOOOONG time (sometimes until Optics/Astro on a really bad one

). It also makes a good early-war trait regardless of that with the extra space for whip anger and the quicker 3rd promos on units. Unless you are running a big empire or are specifically happiness-crunched early, I don't see them as "powerful" as the better traits though.
After that I kinda see the rest of the traits a grab bag of sorts. Other than PRO being the bottom of the barrel I don't think too strongly about any of them in particular.
EXP I've never thought very highly of, and not for a lack of understanding the trait or how it works. Just a middling trait IMO. Shaving turns has a limit of usefulness, snowball or not. It's the whole no anarchy with SPI argument over again. Yes, slightly faster workers is an advantage while you still build them, and yes cheaper granaries makes them stupid easy to emplace whether you care to whip/chop them or not. I enjoy both aspects of the trait, sure...but nothing gamebreaking to the point that literally every other non-EXP civ on the map is gonna be behind or anything. You can't make a power play with EXP like PHI or SPI, it doesn't offer economic cushion or help to dig out, it doesn't auto-pop your borders for you, it doesn't directly enhance your units in war and it doesn't help with barbs. And so on. I do really like the trait for early attacks (axes, maybe HAs) as getting that worker faster and those granaries quicker for earlier efficient whipping CAN make all the difference there in such a critical threshold. But for me, overall an unexciting trait. May as well not even mention the health bonus either unless you are in a FP heavy start.
IMP is a trait I never really liked for the longest time, but playing for a few years has let me see that it makes slow builds of settlers a much more bearable thing especially in low food/moderate hammer cities, lets one toss out gift cities with much less setback, do crazy stuff like forward settle an AI to rob their resources or cut off a land area, etc. It's an entirely different game facet when you can do things like that without stunting yourself as much. I don't think much of the GGs but there's a marked abundance of them so you can go nuts with promos if you want, and it makes that very first super-medic or unlocking the HE that much easier to snag. I definitely have a little bit more appreciation for it after using it some more.
AGG can be either a nice quality of life trait or completely useless. It helps a lot with barbs, enhances an axe rush (or defense!), makes it really easy to produce early 2 promo units (Medic, Cover, Shock) for various uses since Barracks are so easy to get in place. It also ruins 2-pop whipping barracks for overflow purposes, is zero help with barbs if you don't have to worry about them (small island, cornered, surrounded etc) and if you aren't attacking with axes early not helping there either. I like the trait a lot more than I used to after seeing Lain use it in action (and playing more aggressively myself in games). Handy to have in the right situation but won't miss it, pretty much.
PRO...there's not much to say about it that almost everyone already knows. It COULD be quite useful, in the right specific situation...assuming it were unavoidable through diplomacy, no other resource based units are available, etc. In practice it's just not, and this a dump stat of a trait. Fun to do the cho-ko-nu thing or choke a rival with PRO archers, I guess. I think the things I dislike most about it is like AGG, it ruins an early 2-pop building that can be used for overflow purposes on wonders --especially maddening if you are playing Qin specifically.