A few things for context; One, I have been reading tarot professionally for over 20 years now. Two, reversed cards in tarot don't always mean 'opposite' or 'bad' of a upright card. In fact it's more times than not is simply a different meaning unrelated to the upright interpretation. Lastly, if you been around for a while you may have read an article where I took 6 or 7 tarot cards and their location in the game and explained symbolically why that card had providence in that location and was significant. That was written by me 
With all that out of the way, while I have in the past and will again give those that worked on the tarot elements high praise for their work. They did an amazing job truly studying the symbolism of the cards and really applying their true meaning to the game world. A really well crafted experience IMO. A couple minor things I wish they would have consulted me on (humor :P ) but as a whole a REALLY well done job.
My biggest qualm however is the "Sun" ending. While I get what they were trying to go for by how they were interpreting the card I would argue they generally missed the mark. It would be FAR more accurate to describe this as the "Leo ending" or "Chariot Ending" more so than the Sun in my view.
The Sun card is, arguably, the most positive, "best" card in the 78 card tarot deck. Upright it has, traditionally, JUST highly positive meanings. And reversed... one rung on the ladder down positive meanings. It, literally, does not symbolically have ANY negative associations aside from some superficial concerns such as ego bruising others.
For background here is the card in detail;
•Upright: Material happiness, good marriage, fortunes, contentment, success, joy, awareness
•Reversed: Same to a lesser degree, perhaps drawing those that are jealous from shining so bright
•The Sun shines light on all the other cards in the reading, adding to the positive, and lessening (but not removing) the negative
•Sometimes the truth is more damaging then lies
•Arguably the most positive card in all tarot
The Sun card is astrologically speaking, represented by.. gasp.. the sun. I know shocker. The sun is associated with the sign Leo. Keep that in mind going forward.
Now Leo a fire sign is generally described with the following traits;
Passion, strong will but overly so at times. Fire personalities tend to be good leaders, extroverted, rebellious, passionate and enthusiastic. Also moody, short fuse, uncontrollable, quick to anger.
All this remind you of a certain character in a certain ending? V in the sun ending is hell bent on proving him/her self as a NC legend. The passion, desire and determination runs deep. And they have been successful and should be joyful as said success, and have a dedicated lover. On the surface absolutely seems like the Sun card to a T. However this is where things go sideways for V.
In said ending, they toss their relationship out the window just to solidify their "legend" status as pride and ego has taken over and blinds them. And then takes a gamble to with Blue Eyes on a wing and a prayer to save himself from dying. One could make the case with his money and contacts at that point he can't find a safer way to address his impending death? No, because he is so far down the rabbit hole of 'being the best' he has lost sight of everything and everyone that actually matters. He can't see the trees from the forest at this point. And again, his is driven by ego, greed and the rush of it all.
Now this post isn't about debating if he should have torpedoed his relationship or not, or place judgments on V's actions. But to superimpose those actions to the Sun card. And if you do that you come to actions of a person FAR closer to that describing a Leo/fire sign than you do the Sun card. As if that was TRULY a Sun card ending, he'd have his cake and eat it too for the most part. He would have kept his relationship (good marriage), not felt the need to have to prove anything more (joy) and took his spoils (material happiness) and worked on finding a cure (success) that didn't entail a adrenaline rush or potential suicide mission.
With that said, I would suggest the more accurate card for this ending isn't The Sun but actually, The Chariot. Upright the card traditionally means; War, victory (with a cost), vengeance, willpower, getting assistance, ambition, momentum.
The "victory with a cost" being the key to my reasoning. All that seems to far better mesh with V's actions, mindset, probable outcome then The Sun. As really there are way too many negatives for it to be what I would consider a "Sun" ending. I feel CDPR took some liberties or just got the fire sign, Sun meanings a little mixed up. But either case granted it's not a major issue per se, but one as a student of tarot I really felt was worth exploring and discussing as I never felt quite right about it.
None the less, hope you found all this insightful or at least interesting! 