This isn't really a baby naming problem as we have no baby to name at the moment but, I'm curious as to how you feel about choosing a name based on possible nicknames or shortening of the name...
My son's name is Liam & I feel rather strongly about not shortening boys' names so Liam works really well in that regard. Girls' names I have no problem with longer names that can be shortened to use in day-to-day life; in fact our girl name for Liam was Gabriella which would have been shortened to Brie (not Gabby or Ella).
I thought I was pretty safe with choosing Liam and having this "issue" with shortening boys' names AND nicknames...turns out my in-laws (why is it always the in-laws??) started calling him Li-Li the DAY HE WAS BORN! I cannot stand how that sounds, how it feels to say it (I never myself ever called him that), what it makes me think when they call him that...I like nothing about it yet still they managed to come up with a shortened/nickname for my unshortenable/unnicknameable boy name! Thankfully as he outgrow his newborn-ness they stopped calling him that, because seriously, could you imagine a 12 year old being called Li-Li by his Uncle? Talk about embarrassing...and of course, I apologize in advance to anyone who uses this & loves it, I just do not!
So, do you have a preference for length of names & nickname-ability for gender? I like the shorter boy names & longer girl names - plus they sound better with our last name! Admittedly, my name is a longer name and way obviously shorten-able so I could totally be biased...
And totally off topic - do you ever use the Must Sound Good When I Scream It name test? I especially use that when testing out how the first & middle names sound together :)
Oh, what a very interesting topic! I LOVE to talk about nicknames, because I am sooooo inconsistent: sometimes I will say one thing Very Strongly, and two minutes later I can say the opposite thing just as Strongly.
And I'm picky about nicknames: I consider some nicknames "legitimate" and some nicknames NOT, and who gets to decide what makes a nickname legitimate? ONLY ME. I will claim it "just IS that way," but then I will make a ruling in the opposite direction on a similar issue (or even the SAME issue!), and I won't bat an eye when I say it "just IS that way," too.
Where were we? Oh, yes! The first issue you bring up is the maddening one of people using nicknames when you don't want them to, which is something we touched on in the post about the name Devereaux. I think it's almost impossible to prevent a determined Nicknamer from nicknaming a child---and as you've found, they can nickname ANYTHING. If you'd named him the letter L, they'd have called him Elly-Elly-L or whatevs. But aside from the very determined (and why IS this so often the in-laws?), the trends are on your side if you want to avoid nicknames: never have there been so many Jameses and Williams and Elizabeths NOT going by Jimmy and Billy and Beth. (Okay, fine, I have no idea if the "never have there been" part of that sentence is true.)
Shoot, I've lost my place again. Oh, yes! You wanted to know if I had a preference for nicknameability of names, and if it was different preference for boys and for girls. So far, what I've noticed is this: I don't mind if a name has a nickname, as long as I LIKE the nickname. I've rejected names that I loved in their full forms but disliked the nicknames of: I knew I could control what I called the child, and that I would have some control over what my friends and family called the child---but that I would have zero control over what the child wanted to be called, and that the child might choose the very nickname I hated.
I notice that I tend to prefer shorter, more common boy names: of my four boys, none of them goes by a name-based nickname yet (I say "name-based" because we're the kind of family that calls people Hedgehog and Blue and Fry). I tend to prefer longer, more elaborate girl names: I call my girl by her long name, but almost everyone else in the family calls her by an approved nickname and/or by the non-name-related nickname that occurred spontaneously when she was a baby. Because I liked playing around with nicknames as a child, I do like girl names with nickname potential.
You also asked if I use the Scream Test to judge a name's suitability. I use something similar, which is the Nag Test. I say the name in this sort of sentence: "Name, did you go potty?" "Name, did you finish your homework?" "Name! I said to put away your shoes!"