Just watching the IGN pro league tournament, and I thought several things, that could be improved.

1) The gold gained font could be shown as the color of the team. (not so important tho)

2) I kinda wish, that I could actually see how many barons/dragons each team has gotten somewhere in the interface. Kinda same as on top you can see how many towers the team has taken down. Now surely you can actually see which team gets the gold, so it isn't so bad, but for example if you do not watch the game from the beginning, it would be nice to know how many dragons/barons each team has taken.

The Purple Team should be Pink Team instead, so pings and units are easier to see on streams.
(and of course much more manly and fabulous)

I always thought that spectator mode would be better if the health bars showed up as purple and blue. Showing one team as red just kind of automatically paints them as the bad guys, y'know?

I love that on the minimap, they changed things to being blue/purple. But I would like to see even the HP bars be team colored, rather than red/green. Wards, too.

It's more neutral if you set it up as team colors rather than red/green. At the onset of a match, if it's between two teams that I don't know (or if I just don't care who wins), I always find myself rooting for the green team because I'm used to seeing my allies as green.

I definatly would like to give my support to OP's #2 idea. How many times does it happen that casters have to comment "Wait, who got dragon there? I think purple did? Maybe it was blue...hang on...can you buy a doran's blade plz? Let me just calculate the gold here...hmm...."

I think a dragon counter on the HUD is needed :P

Even out of spectator mode. You sometimes wonder if your team got dragon or not. Would be nice to have a counter for dragon in-game. Probably a counter that only shows you how many dragons your own team got. Don't want to remove the possibility of enemy team doing dragon secretly.

Those colors are still very close though. I would go for red /blue... but that's just me, I guess.