I am of the opinion that ranked won't fix the issues with populace. I think it will help with the mode hemorrhaging players, however.
I am also of the opinion that balance changes won't help with the populace. Something more drastic has to be done with the mode in order for it to gain numbers. Riot sponsored tournaments, riot streams... something. Maybe first win of the day bonus for Dominion.
I agree that something more has to be done, hence the 'promotional work' part of my post. I've long been advocating the launch of a tutorial mode from Dominion, and I'd love to see featured streams and fansites (DominateDominion). I want to see more Rioters playing Dominion and inviting players to their games. I want to see more people saying, "Hey! This is actually really cool! You should come check it out!"
That being said, I believe the next steps should follow the following order:
1. Balance game to grow viable champion pool to something comparable to SR. No more than 3 mandatory bans.
2. Promote the game mode through featured streams, featured games, tutorial mode, and Rioter support/participation. Double IP weekend?
3. While (2) is in high-gear, and not until after tutorial mode is released... RELEASE THE KRAKEN. AKA: Ranked.
In my armchair view, it's all downhill from there.