Even though I'm not necessarily in line with Bucky's comparisons, I totally agree that things should stay the way they are.
Most people who complain about Cards being op and wanting restrictions seem to be the ones losing against the higher leagues, but these are indeed not there to be beaten easily or with unupped beginner decks, Platinum decks are meant to be close to unbeatable to newbies (as are FG's)
No experienced player seems to have problems with these decks or the (lack of) deck variety you face in the Platinum league.
I find it has always been like that, even with the old t50, there have always been "decks of the moment", at some point, all you faced was Rol/Hope, another time GotP/Nightmare, then you felt like all you faced was Fire Stalls or I've GotP time...so now it's Rainbow decks... where's the problem?
As Bucky said, if you can't beat them, play a lower league.
My system to avoid being bored: I play one match in each league, Bronze to Platinum, then I start over, trying to get the extra-spin in every league, this way, I play a great variety of decks and every league is actually interesting.
So no limits, no restrictions, I like the Arena the way it is.
First of all, do you think you are more experienced than members who suggested changes? I don't think so.
You probably didn't understand that some people want to make Arena more interesting. And that goes for deck-builders and also players facing the decks. It isn't fun facing a 500hp deckout-deck or almost the same (rainbow) decks over and over again. It's also not fun having the same rainbow or stall deck and just put whatever 5 cards in it.
IT IS NOT FUN NOR FOR THE GUY BUILDING THE DECK NOR FOR PLAYERS FACING IT.
This is a game and as a game it must be fun above all.
I really support excluding SoGs (it's absurd having 12 sancts and 12 sogs in a deck) and a system like majofa suggested or something similar which will force people to be more creative. Bronze and Silver could have less restrictions so that newer players can still build some decks and submit it with their limited cards.
Even if Arena means prestige for many people I would love to see new ideas there, new card combinations etc. Ideas you can carry on for making your FG or PvP decks. And also I dont think Arena gets you so much money after all from the deck you submitted - in whatever category you are (ok it gives more to plat, but people there don't really care about 200-300 electrum).
So why not make a duo strong deck you just figured out with the card given instead of submitting the same old stalls and rainbows with that card stuck in?
Have fun