Tbh the point system is not 'stupid' because its fair enough since you are facing an AI not a real person.
As far as i experienced on arena points, is that the major cause of this 'stupid' calculation is that the game calculate your Rank diffence points by a strange (kind of unfair but meh you fight an AI..) gap.
For example you have X250 points u gt matched with someone slightly higher than / equal with you lets say X260 the max rank diff point you can possibly get is 4.
BUT if you gt matched with someone even if its only slightly lower than you lets say X245/240 the game will gve u max 3 points.
To get max points (5) you need at least a significant amount of point dif like 50+ points higher than you (if you are @X250 you need to face enemy with X300 pts to get max rank dif bonus pts). While you get the min pts (3) bonus if you fight sm1 with 5-10~ pts lower than you.
As for the other two bonus points is pretty clear how they work, calculating numbers of heroes remaining between players and tile point difference.
Can u explain how points are calculated when losing (if u could)? I'm curious myself coz whether I lose in close battle or I lose drastically, I seem to lose the same points.
Well I did a test for this lets take a look :
Heres is the opponent, I have roughly close to 50 points dif lower than him. As I said on my prev post if I won against him i'll get guaranteed 4 Rank pts bonus. So what happen if i lose against him ? Lets find out
Oh crap I lost ! (Rip points) lets see the scoreboard
First the Hero loss pts, i forgot to take a screen how many of my heroes were alive at the end but if I remember correctly I had vincent, cybella, and darrion alive still. Why I got -3? I have a theory imo the base pts whether you win or lose is 1 / -1 and each hero that got killed adds 1 or -1 to the score but they cannot go higher than 5 or lower than -5 (this is just my hypothesis), so basically since I lost the match i got -3 (-1 from base pts and -2 for cause my gr cybella & kira got killed).
Second the Lead pts, now this is what usually "kills" your points. It looks like that this score has a base pts of 3 or -3 (again its just my theory), therefore its kinda complicated how to calculate this. You can see my opponent leads by 26 points and i got -5!!! Holy crap, but lets guess what are the caps on this score? Well just my guess but i think its like
[25+ lead points dif = -5 if you lose, 10-24 = -4, 0-9 = -3]
As for the third one which is the Rank dif pts, I pretty much explained my theory in previous post, if you lose against a higher ranking with 50-100 pts higher than you, you will get -3, if your point dif is between 0-49~ range you get -4, lower than that is -5. I have 44 pts lower than him so -4 for me.
So in total i got -12(rip) points.
This is all just my theory but hey who knows if part of it might be true.