i noticed every time a quest popped up. it was fine, i dont want something big flashing in my face during a teamfight or some loud annoying sound when im listening for enemy spells to dodge. I think it's perfect the way it is, Just need to pay attetion

Yep, I didn't know quests existed until after the game was over...I was so focused on the towers and players.

I had a hard time noticing the quests as well maybe for example you know the emblems next to the capture points on the mini map? well maybe if they glowed and/or pinged when the quest points are marked so that people would look at the mini map and easily be able to to tell a quest point is up and the ping would sound off when the quests start.
I thought that would be cool since there was that emblem there on the mini-map anyway

Maybe make the minimap icons flash or something? Perhaps have the words that show up in the kill announcement area be a brighter color? (they were..blue, I think? All I could tell was that they contained the word 'quest' in them.) I barely noticed the start of the quests, and my teammates were all like 'hurr let's go defend an irrelevant point now'.

Just to be on topic, I only got to play 1 game and I noticed the quests as soon as they popped up and with just a small amount of intellect figured out which points they were talking about. (Hmm the ones at the bottom? lol)

I'm sure the current alert is fine and once people get used to playing Dominion they'll catch it everytime. (Some people were probably either too excited or too confused to understand what it was talking about)

Yeah I only played one game, but I didn't pay much attention the quest. I think it will be fine though once we get over the initial shock of dominion and begin to look around a bit more.

I knew there were quests, but I had no idea how to be able to see what I needed to do.

Needs improvement!

I think you should have have the announcer lady say something like "A new objective is available"
And then have a distinct ping on the minimap. Anything more than that is just bad awareness.

As far as quest display goes, you've already introduced something like a objective marker with orianna. Would it be possible to set something up with dominion so that quest objectives display in a similar manner for all champs? And you could use different icons as pointers. A sword, a shield, etc. As long as they are able to overlap without any confusion, even for orianna herself, then there shouldn't be any big problems.