I don't think Dominque will be a starter, but I could be wrong. Chyka was saying they are still looking for a starter, so that sounds like they also don't think LD is starter material.
Chayka is probably looking for a starter for this season, but that doesn't mean that LD couldn't step in at some point in the future. He said he wanted to get younger in goal, so, typically you look for a player that has done well starting (or a fair amount of starts) and continue to develop the BU if they have the potential of being a starter.
We got slightly younger with Johnson (if re-signed), but I figure he's looking for a 27 or 28 year old goalie (perhaps Raanta) who is ready to step in as a starter and hopefully keep that position for a season or three while you focus on the BU's development and incorporate that player into the lineup more. Once the starter starts to decline, you switch the two for a season or two while exploring other options for the next possible starter (prospects, trades, UFAs). Continue the cycle while developing the rest of the team and the team can become more successful.
Of course, I'm not sure LD has the potential of being a starter, but he has shown that he can do well if given the right chances and opportunities to succeed. With a middling starter, LD will have those opportunities; if he does poorly, we look to Hill, Mishka, or possibly Madsen. If the prospects aren't ready to move up to the BU role, than you hunt elsewhere.