Im level 30 now and have done every instance possible so far. The thing that stands out is ofc. the lack of convos, but also the boss mechanics. For lack of better positivity I'd like to point out how cool some of the boss mechanics are, and I sure hope Operations will be this challenging in the future!
I agree, most of the bosses do at least something interesting. The ones that stand out (up to Boarding Party):
Hammer Station: Last boss is a good skill check, refreshing to see good play required this early in the game.
Mandalorian Raiders: The 2nd boss is a bit overtuned but oveall I love the fights here. The first boss with the untauntable dogs on top of the AOE mechanic of the main boss is really neat. Last boss is a little easy but the idea is cool and the fight feels epic.
Cademimu: Love the nod to Kael'thas fight in the first boss. 2nd boss is a bit boring, but the last guy is also suitably epic.
Boarding Party: Lot of ho-hum fights here, but the first boss and last 2 bosses are really awesome. First boss is just visually cool with lightning filling the room. Last 2 bosses are really challenging and took a wipe or 2 to figure out.
Overall the difficulty of these fights is great, they're not impossible but they require people to play above the level you'd normally expect for leveling instances.