Bards and Merchants.
If the "great" version of each were given some modicrum of "OOoo"ness if attached to a city (AS a citizen) then each of the specialists would find more use.
Why not give "great" bards a +1 Happiness to the city. I mean, A) you're not using that great bard for a variety of other things, B) his bonuses to culture dont outweigh the "bomb" effect he normally has.
Actually, the Specialist is better than the bomb but it just takes slower to get into effect, and is of course depending on when and where in the game you do it. The +3 Gold is really good actually, since it's a base sum, affected later by % bonuses like God King's +50%, and +25% from Tax Office, the +100% from the Bazaar of Mammon, etc. And it is unaffected by the slider, so it increases chance to research at 100%.
Look at this example:
That's from two great merchants, two Merchants, a market, and RoK Temple. With A Bazaar of Mammon, Tax Office and Money Changer, under the God King Civic. And this doesn't even take into account the +1 Food that great merchant gives, which enables you to work more mines, or Towns on plains.
With so few buildings to give base culture in FfH, the +12 Culture from a Great Bard is HUGE. When all % giving buildings and civics are applied the culture you will get far outscores the bombing. For example, on Epic game speed, the culture bomb will give you 6000 culture. But that doesn't help you much if you don't get to 7500, and that last 1500 can be hard to get in any decent time. In fact, that 6000 culture have the same border size as 750 culture, just with some extra strength. And while you work your way up 6000 culture, the +3 Gold per turn is gonna help a lot. Of course, there are situations where the Bomb is probably a better idea.
Here's an example:
This is with 4 religion temples (OO, Order, Leaves and RoK) a Great Bard and Bard.
And the fact that the Great Bard gives 3x as much as the regular specialist compared to the other Great Specialists that usually just give double the amount, is pretty remarkable.
Now, consider the above example, but with 3 Great Bards, and the culture slider at 100%. Now that is a cultural monster
The great merchant could (as I see it) add an additional trade route. +1 Trade route as a Citizen Great Merchant would be significant. Or perhaps he'd add 1 gold to each "active" trade route. Thus, if you got a few Great merchants in your city, each trade route would be getting added benefits.
That would either be to STRONG or too WEAK depending on circumstances.
Either of these options added to great bard and merchant "citizen" qualities, would make them more appealing to use as citizens, and would make their specialists more appealing to use to GET the great folk.
I think that the specialists are unappealing to people cause they haven't really analyzed the effect or tried it in practice. My above examples are great to show what the specialists can do. I think people HIGHLY underestimate the great specialists. Another great thing with great specialists is that they are affected by the civics that increase output of specialists, like Caste System and Scholarship, which, if you have both, would make every great specialist give another +2 Research, and +2 Culture.
Having said that, I'm not against improving the Great Specialists. Especially as Agriculture is getting toned down. But improving on them might risk breaking the balance. And again, the great specialists
ARE better than most people think.