Hello guys, I would like to revive this discussion about gold and upgrades.
My experience in this Skylords game:
Played a couple of days when it launched (because couldn't stand at hard logins and crashes) and now - 5 last days.
I now have fully upgraded (except for charge upgrades which isn't always that useful and considers BFP and not gold) Nature - Frost deck, which includes Shaman, Coldsnap, Grimvine, Promo Grinder (without any multiaccounting).
My experience in EA's Battleforge:
Started actively playing more than a year before and till the shutdown. I did spend some money to get some cards and was having very similar deck like I have now. But my deck even after a year of playing was never fully upgraded (regarding normal upgrades).
Back then it was worth playing PVE and there were more players at PVE than rPVE. Now, it is so fast to upgrade a deck - rPVE 9 lvl gives about 4 500 gold and the upgrades for a rare card cost (1) - 1 000 (+400 to upgrade) gold, (2) - 2 500 (+1 000 to upgrade), (3) - 7 500 (+3 000 to upgrade). So, to get a fully upgraded Rare card, you need 15 400 gold. You can make that in 4 rPVE 9 difficulty games (~18 000 gold), which takes 4x20 min = 80 min. I am not even talking about common and uncommon cards.
Ultra Rare cards are trickier, because you need a high level to upgrade them. But still, your deck at start will rarely have any Ultra Rare cards because they are limited by boosters and BFP.
So, in my opinion, farming gold in rPVE is way too fast to upgrade cards. That being said, PVE seems like unrewarding and useless to play as you have to play for about 30 to 60 min (depending on map) to get 1 to 4 upgrades of random cards, starting with Standard difficulty for first upgrade, Advanced for second and lastly Expert for third. All in all, you will take 90 to 180 min (depending on map) if you are lucky to get needed upgrades at the first time, to get all upgrades for 1 card - this includes not only Rare and Ultra Rare cards, but also Common and Uncommon which you can fully upgrade after 1-2 runs of rPVE 9 level. I even heard, that speedrunning specific maps is even more profitable, but never tried that as it requires a specific deck.
As far as I remember the old Battleforge, it had more players in PVE than rPVE. Here, as far as I know, people go to PVE mainly for quests or solo speedruns.
I would suggest decreasing gold received in PVE and rPVE so playing PVE would feel rewarding for those card upgrades. Current upgrade system shortens the life of the game and discourages increased playtime.
Getting good cards should be challenging (or lucky). Getting these cards even better should be even more challenging - by getting a card, you unlock it's properties for use, so that is sort of an "achievement"; making it's properties work better should be a harder achievement focused to more like an end game. Now I came to the end game and not really sure what should I do next except for waiting for next day to complete quests and hope to get better cards to modify my deck (and using gold to upgrade cards that I don't currently use). And all in all I was playing for about couple of weeks. As I compared above, I couldn't achieve that much during more than a year in EA's Battleforge while considering upgrades were always free to play content.
P. S. I think it is tempting to get best cards and all upgrades ASAP. But it isn't how Battleforge worked and it isn't how any other long-living game works. I think all the PVP players pushed this upgrade system to this point because they don't like playing PVE. But currently I see PVP being played much less than other game modes.