after gen 2 pokemons changed a lot, all movepools changed, move tutors and a lot of shit. on gen 4 zam lost ice punch(Cant use because it became physical, together with the other 2), i was trying to say that on gen 3, 4 and maybe 5 there was almost no pokemons that lost anything, its just the metagame that fucked them up.
sorry i was not specific on that post, i should have said gen 3 and further instead of after gen 3 started but my point is that besides specific examples like zam(Who is the best example IMO) no pokemon lost any useful moves gen 3 and beyond, abilitys(not even possible) or anything of the sort. they all won something, its just the current metagame that make then look worst then they are.
zapdos for example is weak to SR but that dont make him any worst then he actually is, its just that the metagame is filled with SR. on the other hand he won a recovery move, a powerful fire type special move and shit like u-turn that all add to his movepool and this will continue on gen 5 with new moves, a pokemon can show up and counter zapdos but this dont mean zapdos become a worst pokemon, it mean another pokemon beat zapdos for a reason or another. Lucario is another example being a pokemon with great movepool, typing and somewhat useful abilitys, only because gliscor counter the most common Lucario set doesnt mean Lucario lose any effectiveness. he continue to be the same old jackal with great movepool and typing.