I totally agree with what you said about the use of different cards in different leagues. I remember doing well in the Silver league but struggling in Bronze after the end of season. The variation in rulesets also keeps the game fun and challenging.
I also do think that the developers are trying too hard and doing too much with regards to the economy. I just hope it doesn't end up with an economy that's hard to navigate, especially for newbies.
Yeah, even since this post there have been a number of things the developers have proposed to adjust the economy. I understand the problem, they have 6,407,000,000 DEC out there, and they're only burning 20,000,000 each week - so it'll take a long time, or a lot of newbies coming in to burn that DEC... but, if they make it too complex then no new people will join further exacerbating the problem.
The other problem is simply that... Splinterlands is very much a luxury expense and those are the first things to be cut in economic downturns.