While not a fan of cornertime...it works.
I have a strictly father/daughter relationship with someone and he puts me in the corner for 10 minutes after every spanking, no rubbing, panties up, pants down - to think about it all.
I hattteee cornertime...but it's part of the punishment...then...the hugs and kisses and rubbing and lotion come after.
I don't think it takes away from aftercare, because it's part of the punishment and aftercare is for after the punishment.
Playtime? Hmm I think sticking me in the corner in the middle of a play spanking would just drive me nuts which could be fun
The only time I am against it is for extreme punishments. If I am getting a serious spanking for lying or something (not that I lie, but hypothetically speaking), putting me in the corner after will make me feel lonely and sad and rejected. Chances are I already felt awful enough and putting me in the corner won't help.
Now, cornertime won't help any if you fall asleep while the spankee is standing there *grin*wink*