HALFPINT
I am afraid that you question is not sensible.
Let me firstly say that I am not an airline pilot, but I have made several hundred landings as PIC of a light aircraft and have done about 15 hours training in an airline simulator.
The point about landing any aircraft is that you need arrive within the landing parameters for the aircraft type (i.e. don't break it) and to stop by the end of the runway. Airline pilots generally aim to arrive in the first 1000 feet or 300 metres of a runway, which is known as the touchdown zone. All landing performance calculations are based on this happening.
So when you Ryanair pilot touches down firmly, s/he is ensuring that the aircraft arrives in the touchdown zone. If the runway is wet, then an extra firm arrival may be mandated to mitigate acquaplaning, by forcing water away from the tyres.
If landing in a strong crosswind, the pilots of some types may well choose to land wing down, with the result that you hear three bumps, as the into wind, downwind and nose gear all touch down seperately. Again I don't know if the 737 800 is landed this way, since the engine pods are slung quite low.
So what the crew are telling you is true and their grimaces are just a reaction to the bump as you touch down.
As I don't fly airliners, you 'll have to take the next line as an opinoin, maybe a 738 driver could help me out here, but I don't think (from visual perception when last there) that Ciampino has an enormously long runway by 737-800 standards, so I would hypothesise that the crew definitely do not want to float very far (or at all) as they flare for landing, thus firm touhcdowns may well be SOP.
Finally, don't forget that a landing that feels firm in one part of the cabin may feel like a greaser in another seat. Also aircraft do sometimes decide to go down with a bump despite the pilot's best efforts :-)
So is the era of light touchdowns over..... well I don't think that it ever started to be honest.