And so, here are mine.
Warning: Text walls ahead.
Thought 1:
Elemental Rank:
A new player (not a reset account) starts of as a Base elemental. After getting 500 points (and thus completing the current quest-arc), you get auto-upgraded to Junior Elemental. From there, you could have the option of spending 100 Electrum to change your rank 1 step. From Junior Elemental, to Mature Elemental, to Elder Elemental, to Master Elemental. Sort of a risk/reward tradeoff: By going to a higher rank, you can get more money, but you lose more per loss. Also affects PVP, in that when searching for an opponent, you can only fight someone of your rank. This means that Noobs don't have to worry about getting stomped, and more experienced players can ignore that pesky feeling of 'guilt' for destroying the dreams of said noobs.
Every 250 pvp wins (or some other arbitrary number) an offer of a free upgrade to the next level will appear. After 750 wins with no acceptance of this free upgrade, it happens anyway, to stop people noob-abusing. Hmm. Maybe those numbers are a bit big...
Optional: Ignore the part about risk/reward for better electrum income, and just make it a PVP ranking thingy.
Multiple Upgrades:
Rather than a single 1-off upgrade, a different method could be used:
Each card could have 4 upgrade options, each upgrade doing one of several things, be it reduce the card cost 1 step, increase creature/effect damage/duration, etc etc etc, but each successive upgrade costs more and more and more. If we stick with the 1500 electrum per upgrade formula, that would mean that a basic pillar could be upgraded to give 1 extra quanta when summoned (for 1500), then upgraded to give 2 quanta per turn (for 3000), and so on etc etc (The next upgrades costing 4500 and 6000 respectively), thus meaning that even the most dedicated farmer would have trouble upgrading all of their cards to the uppermost levels (example: 30 cards, each card has 4 upgrades with increased cost per upgrade, so to upgrade one card fully would cost 15,000, and that multiplied by 30 is 450,000 electrum. And that's a minimum size deck with a uniform number of upgrades per card, rarer cards could go for even higher levels of upgrading)
For added tactics, letting the player pick which upgrade to have could add all sorts of fun. Two people with identical starting decks could end up with wildly different cards depending on which upgrade options they pick, especially if there are more options than available upgrades (If a card can only be upgraded 4 times, but you have 6 options, which ones do you sacrifice?) (This also means that Fake Gods can keep their level of immense power, by having cards that are upgraded beyond the limits*.)
*yes, this means that beating fake gods to get upgraded cards would stop, as limit-break cards like this in PVP would be unfair. Instead, fake gods could give away different prizes, like reward cards that have no in-game function (like the basic shards), something like divinity fragments. X frags* (and it would not be guaranteed to get even 1 frag from a FG) could be then traded in for 1 free upgrade for a card. It's all about risk/reward and balance.
*Where X is a suitably arbitrary number
Item Quests:
Sick of never getting that particular rare card? Wish there was something you could do about it?
Go hunting for it of course!
Currently the quests button is a bit sad and empty feeling (after 500 points, anyway). One addition it could have could be a "Go treasure hunting" button. There's a variety of ways to do this, of course. A very easy way: Fight an AI opponent. If you lose, oh well, back to the main menu. If you win, choose a direction (north, south, east, west). Fight another AI. Choose direction. And so on and so on. The hunting sequences would have to be quite lengthy, to prevent deliberate farming. At the end of a sequence (say, ten or so battles and direction choices), you gain a number of Palladium coins equal to some value based upon your performance in the previous ten battles, and your direction choices (This is obviously iffy, so some way altering each direction's risk/reward per sequence would need to be implemented)
And then, spend your hard earned Palladium coins on rare cards, at the Bizarre (Because it's some kind of swirly wormhole thing that exists between dimensions, or some gubbins like that, and is a delibarately poor play on the use of the word "Bazaar").
The cost per rare card in Palladium would of course have to be prohibitively high.
Why Palladium? I dunno, it just seemed like a good idea. It's a more valuable material than gold. Why is the normal Elements currency Electrum (an alloy of gold and silver)? Some things we will never know... (Hey, we could go with something way out there like cobalt! It's magnetic!)
And yes, some cards should forever be in the domain of the reels. But just to spice things up, some cards should only be obtainable at the Bizarre (or by other means), and never show up in the reels after a match, no matter how many times it's in a deck (just to spice things up a bit).
Oh, and in case you were wondering: No, there should not be any way to exchange electrum and palladium.
That would be too easy
Non-battle Reels:
A handy device for the rich: spend 100 electrum for a spin at reels which have every single card in them!
Obviously, using the standard reel mechanics, this means a pitifully low return for the investment, but there's always that slight chance that you'll get Eternity or somesuch, which will keep people coming back... (In game mechanics terms, this is a way of removing excess electrum from the game. Of course, very few people will use it in the end, since they will be disillusioned with getting either nothing or pillars, but it's always nice to have the option...)
Character Upgrades: (plays into the rank idea above)
This is bound to have been thought of before, so I will add my own version here.
Pay an arbitrary amount of electrum (Or Palladium, or sacrifice a rare card / X reward cards). Get one of the following permanent upgrades:
+10 life.
+5 starting quanta (of a particular element)
Everknife: Basically, you will always do 1 damage a turn. This gets replaced if you use a different weapon card, but if that card is stolen/destroyed, the everknife returns. And of course, it can't be destroyed/stolen.
Poison resistance: Ignore the first poison effect of a match.
Powerful mark: Your mark gives you +1 quanta per turn.
Spell resistance: Resist the first spell effect cast on you in a match
And other such sundry thingies of this sort.
Each upgrade you get could force you to go to a higher rank, again to prevent PVP noob-stomping.
I think that's all i've got for the moment. I'll post again if I think of more!
Oh wait, one more idea...
How about being able to Mulligan? (A joke!)