First of all, big warm welcome to the game. It indeed is a great game and it's good to see that you're enjoying it.
The highlighted rarity cards could be cool/useful and I'm not against the idea. It would totally make it a lot easier in the deck builder to recognise them. I don't find it neccessary though because when I contruct decks, I don't even look at the rarities; I look at which cards combine effectively with others.
Regarding a way to watch matches between players. Mike, check this out if you haven't already seen it:
https://www.kamcord.com/developers/I'm not sure but I speculate that you would need a powerful device such as an iPad3 or iPhone5 or better.
And to add in a function to display the cards in the discard pile, yep it's been requested.