Does NiMH have this same characteristic of wanting to be charged at 1/10C minimum?
No, NiCads don’t have that characteristic either. It’s just a common (though not universal) recommendations from manufacturers. Too often people will try to apply extra meaning to recommendations that was never intended. I am going to order a tranny pack from you and am trying to decide what to get. I don’t mind long charge times. I am trying to avoid a decreased capacity situation.