You asked and i can deliver:
(disclamer: it was right after the first patch to the card system, so diamond prices, possibilities etc. are from the old system.)
I will refer to "Soulstones" as dust and just call the colour when i talk about specific shops and such.
I didnt really farm cards before so i had 0 blue dust and decided to farm for around 2 hours and see where it gets me.

After two hours of farming the instance for blue and purple cards i got 120 blue and 20 purple cards (was farming with over 1k drop the entire 2 hours). I decided to try and make myself a nice blue card.


After making all the bad cards to durst (118 blue and all of the purple cards) i ended up with this as my dust:

I play as a mdps and therefore i need intelligence and magical atk primarily on my cards with something like lp or durability as a bonus. Out of the 120 blue cards i farmed i kept 2: One with a high magical attack Value and one with a high intelligence value. I decided to upgrade the card with the high Matk value. That meant for me to add intelligence as a stat and make it as high as possible. So i started rerlolling the shops until i found the stone that added a random attribute as well as the stone that locked my matk value and saves it:

The next step now was to either get the stone that changes physical defense to something else randomly or the stone that changes it to intelligence. I was very lucky here after rerolling a couple times. (11 times maybe) i got the stone that changes physical defense to something random which i used and got magical defense. I also found a stone that changed magical defense to something else and it got me intelligence.

At this point i was already almost 3 hours into card farming and rerolling and got pretty frustrated (granted i didnt really know what i was doing at the time, needed to read all the stones descriptions and probably rerolled some stones that i should have kept).
I then decided to go for at least + 10 intelligence on the card and started rerolling my purple shop. After rerolling the purple shop a couple times i bought around 10 of the stone that changed all my attribute values at random on any of my cards. Because my Matk value is locked it only changed the intelligence value. After rerolling my value a couple times i ended on this:

But thats on me i guess i got too greedy?
So after approximatly 3 hours i was very frustrated and i spend around 2k diamonds in total on one card which ended up bad anyway.
I also saw that some of the problems are adressed in the patch notes, thank you very much for that. If i understand correctly getting the correct stones wont be that much of a pain after the next change.
But i want to summarize what such a system means for me:
Even after the changes this system will be a huge time investement. This is fine (or at least i think so) when you exclusivly play one class. If you like to multi class and play both pdd and mdd or even heal or tank there is nooooo way in hell that you do the card grind for all of your classes. Even doing one to an accaptable level seems very much like an impossible task. So even if there was a system in place that lets you input one card multiple times (for your other classes) there is no way that you can do the grind once more.
-> with such a system in place one of the biggest strong point of this server dies for me.
(and there is no way i spend any of my resources on another gear)
~kind regards Noodlez