I like the idea of themes, but to me how ticklish the model is, is the primary factor. If the ticklee is not ticklish or attractive then I wont consider it.
I DO NOT like Nylons, to the extent they are actually a turn off for me and I dont buy any clips that have nylons in at all. They remind me of my Granny's feet (not good), I always expect there to be big chunks of hard skin hiding beneath. Thats why I like bare so much more, I can see they really are soft (or not, in which case I dont buy either).
I know a lot of guys like nylons and they do bleet about them ALL THE TIME, but I guess that is because not as many clips are made with Nylons. I suspect the reason for that is because Nylons offer that extra lair of protection so it is harder to get a reaction from the ticklee. So if you want extra ticklish you take away that protection and have the girl go bare foot.
Then if you want to make her even more ticklish you apply baby oil to her soft bare feet and use a brush!
I think even the Nylon lovers out there would agree baby oil on nylons just doesnt work.
Strangly I dont mind socks and even quite like sock removal (as long as a clip has lots of bare foot tickling then I will still consider buying it even if it has some socked foot tickling first).
So assuming you have an attractive ticklee who is super ticklish (and prefarably a "can not stand being tickled" level of ticklishness) who is well restrained then story lines / themes I would enjoy are.
Naughty School Girl / College Girl being tickled as punishment and having to make certain promises in order for it to stop.
Harem Girl being punished for something and having to promise to be good.
Although I have seen both of the above story lines (to more or lesser extent) covered before they have not been done with a superticklish ticklee (in my opinion) and hence there is still space for a great tickling movie on those themes.
In my opinion Tickle Paradises best ever clip was the one with Lilly being tickled for information called Spy Interrogation.
MY favourite storylined / themed tickle movie to date is from Real Tickling, called 'One Young Laughter' starring Little Robin. Little Robin is super ticklish, super sexy and gets to wear progressivly less and less clothes as the scenes progress (its almost an hour long) and gets put into more and more restrictive restraints. She even gets made to beg to be tickled. For example at one point whilst tickling her bare feet the TIB says, "Say I like it so much please keep doing it" and she does and you can hear the hiesitation in her voice, then a little later on he makes her open up her arm pits (she refuses the first couple of times but he just tickles her worse until she submits) then once she has done that he puts his hands in her armpits and then tells her to "Say Please" once she says "please" he says "Please Do it" again as she repeats his words you can hear the hesitation in her voice as she starts to laugh in anticipation. The TIB even does things like this, he will say to her "are you happy" if she says "no" he tickles her worse and says wrong answer so she quickly changes her mind. This adds a really great dimension as you can see Robin is trying to figure out what to say to not get tickled so much. For example in a following clip (not from that movie but from Hotel Tickle) Robin is Hogtied (bare foot, in just a string bikini, with her ankles and wrist bound together and also her elbows are attached together behind her back for extra restraint), whilst in that position the TIB says to her, "Do you like it between the toes" (it is clear for all to see that drives her wild) she says, "no" then quickly says "yes" so it is clear she remembered her previous 'tickle training session".
Sadly no one seems to make clips like that anymore.
Ok thats my 2 cents worth.