Same. Lancers are notoriously unpopular units around here but as a complimentary piece to an army they can be useful. Sipahi is definitely that kind of complimentary piece. Hakkapeliita I'm not so sure I ever understood.
Winged Hussars however seem like they could be great. Send em in to break the up an enemy line and send em away to heal them up, only to have them come back and do it again (speculation obviously because we don't know how this perk works)
In my opinion lancers/sipahi etc. need the promotions to make them special. Without them they are really frail, but they should be build in a city with barracks+armory and maybe national epic, that way you can choose deadly promotions immediately.
Like a lancer that has open terrain bonus I and II, it's excellent to smash ranged units and cannons.
Of course promotions are always good, but it's essential to lancers (and to ranged naval units, but that's another story).