I tend to think that the advisors in this game would not be comparable with the non-companion LIs in ME3.
We have some evidence of that the advisors would not be "confined to base":
1. There was a tweet by Mr. Laidlaw, where he stated he was playtesting a long quest all over the map with Cullen.
2. The E3 demo showed that Leliana could be taken on quests as well.
From these I deduce that at least for some quests you would be able to have an "outing" with the LI advisors.
3. There was a tweet by Mr. Gaider that stated that the word budget for the advisors was the same as the one for companions, this was not really true in regard to the ME3 non-companion LIs.
So it is quite possible that the advisor romance would be as valuable and meaningful as the companion romance in DAI.