Adaar's loss should have been taken more seriously.

It depends on what options you are given. In any case, people in game aren't going to realise that is why you seem to be acting differently from usual.

First run I tend to play things as I find them unless I find it impossible to complete a quest without "cheating". With the War Table I think the outcome for Clan Lavellan was the first time that something really bad happened as a result of my choices.

I didn't mention it before but first run I tried to opt for the advisor whom I would most like to base the Inquisition around. In other words, I would choose Josephine as a general default because I wanted us to be seen as diplomatic rather than sneaky or martial. We had previously been told, around the time of the 2013 trailer, that we could customise the Keeps in a similar way and that would affect the overall perception of the organisation. Now I think it did make a difference how it was described in the epilogue but considering how frustrating it was just waiting for the right person to become available, it hardly seemed worth the aggro.

After my first run I realised that it was possible to overcome the delay.  I would only instruct the advisor on really long missions immediately before I finished for the day. The timer ran in the background in real time, so when I logged on again, hey presto the mission had completed. That meant I could definitely choose the right advisor where it mattered but just opted for whoever was free for the ones where it didn't. It also meant that I would know if I had messed up before playing through several more quests, so it wasn't possible to just reload and try again without losing all that effort.

As for the Lavellan quest, I checked the Wiki after that first disaster to see what I had done wrong. It wasn't possible to go back by that time so I just played it differently the next game. That poor girl, not only did she lose her entire family but she was romancing Solas! Unsurprisingly, I didn't end that first run feeling very elated at our success. Her standing alone on the balcony at Skyhold just about summed it up for me. By the end of Trespasser she had handed the Inquisition back to the Divine because she was an emotional wreck.

I think there had been so much negative feedback about the lack of reaction to the Lavellan quest, that is why they bothered to include it in Trespasser. I can't remember if Sera mentioned it to my Lavellan or not. Is it only if you are in a romance with her? She hadn't been on good terms with Sera since that personal quest where Sera punched the guy to a pulp because I insisted on questioning him at length instead of just reacting like she did. That was my Lavellan's character. Her name was Atisha because she was known in her clan as a peacemaker and she followed the Atishan, the Way of Peace. That is why she preferred to adopt diplomacy where possible. Sera really rubbed her up the wrong way and she hardly spoke to her after that incident, although stopped short of kicking her out altogether. So, it is possible I missed the conversation in Trespasser because we weren't on speaking terms.

As for Adaar, perhaps not enough people played as them and from those perhaps there wasn't the same negative feedback about the personal quest as there was for Lavellan.  I agree that having someone joke the loss, even if only off screen as a War Table character, is not really in good taste.   However, there was a bit of a tendency that way with the writing.   With the Sera quest you can get her to stop by saying something jokey about the state she has reduced the corpse to.   Some of Iron Bull's comments can seem a bit tasteless too when it came to violence and Solas can even admonish him about it.   Actually, a lot of the time Solas seemed to be the one saying the things that I wished I could, which is why I identified with him so strongly and why it really deflated me to discover his real agenda.   Can't anyone be a genuine good guy, particularly as an elf?

Incidentally, that is why it really annoyed me how they were hinting in World of Thedas 2 that Shartan wasn't the real deal and his story was based on an older elven folk tale about a rebel warrior who fought against tyrants, in other words Fen'Harel.   Couldn't they leave the elves with one honest to goodness hero they could aspire to be like?