I still think that the highest tier trainable units are pretty pathetic, attack-power wise. Dragons, Paladins etc. really don't pack any attack-power punch and there's no way to really fix that. 

^That is what I'm suggesting. I know they did a pass on their strength with 5.4 but it doesn't seem to have done all that much. 

Well i can see your point but i would contend it depends on the map size, difficulty level and luck 

- know where to build my next 2 cities(can see tile yields next to shards)

>> Early game you are not likely to be strong enough to fight your way there and on anything but tiny way too far.  IF you get lucky a good spot is discovered right next store.

- have started quests with 4 factions (most of them are located near shards), and completed one of those for 20 mana

>> This one i concede with a caveat : again depends on size/difficulty/luck WITH the way latest patch places their quest locations.  Used to be close to you; now very scattered. So you may not be in any position to do the quest & the clock is now ticking.

- know where the sorcerer king citadel is located (which makes reveal SK useless)

yup but useless * marginally useless still = useless

- know where i can liberate a hero (slayer statue)

??? Did i miss something? Does it really show hero statues ?? if so; the value goes up

not discounting your opinion and based on your observations, can see how it could be useful depending on size/difficulty/luck