I think D:OS can learn some things from Shadowrun returns. Both games have a similar combat system. I have read that they implemented a cover system in D:OS2 as well.
-There is the final battle of dead man switch. There are some adds in the beginning and adds keep on spawning in several locations. You had to destroy the body of the adds with normal weapons. Than you had to destroy the soul of the adds with a special weapon. It was frustrating that the the special weapon had a hit chance of about 50%. There were also structures in the environment and when they activate they give a buff to the boss. You have to attack these structures to debuff the boss.
- The APEX battle in Dragonfall. I choose to defend APEX. Your party had to protect the main computer (enemies want to destroy it) and you had to protect 2 other computers from being hacked in 2 other rooms. You have to enter the matrix to unhack computers. Hordes of enemies are coming to you all the time from different directions.
- The boss battle at Feuerstelle (Glorys personal quest in dragonfall). The boss splits up into 3 (one real and 2 copies) each turn. Sometimes somebody else shows up who buffs the boss and you have to attack him to debuff the boss.
- The final battle of dragonfall: There is one boss and many adds, some of them show up later. You have to use several switches all the time to prevent a countdown from ticking.
I have not played SSR Hong Kong yet. SSR is even more tactical than D:OS1 because you have more limited resources
(only up to 3 weapons, 6 spells and 6 items per char, summons require an item or a weapon slot (drones), hacking requires a weapon slot, you have to reload weapons, improving your char with implants lowers magic power, . . . ). However, D:OS had its wondefull elemental system and world interaction as advantage.
I have played WoW for some time (and I am happy that I stopped playing). WoW had many interesting bosses. But I do not know how well you can transfer something from real time MMO to a turn based single player game. But I guess some things might give you an inspiration. I quit playing when the second raid tier of Mist of Pandaria came out and my favourite dungeon was Ulduar.
Prof. Dr. Dr. Mad S. Tist 
