I'm not very keen on how Leliana is written in DA:I.
I mean, there's all the hardening stuff which I've talked about before so I'll just stick to saying I didn't think it was done very well.
But also for the rest of the game she's just rather boring. I mean, I complain about psycho-Leliana, but at least then she's interesting. Otherwise when she interacts with the protagonist she's either being angsty in a very standard way, or she's being a handy plot device, there just aren't enough occasions when she shows real personality. I mean, you can say that it makes sense because of her job and the stuff that's happened, but the game must take place over like a year, so it's not like she can really be nothing but moody spymaster for every moment, and other characters who have similar heavy stuff (like Cassandra and Cullen) going on still manage to have scenes and conversations that aren't just the same moodiness.
Oh, and the occasional romance dialogues just come across as tacked on and make very little sense with her general demeanour.