More importantly, don't make pronouncements from on high about what the "correct" limitations are, like telling us every world has elves but not half-orcs, or whatever. Instead, show us both how to (a) make those restrictions for any given world, and (b) actually benefit from those restrictions.
And then make it blindingly clear to players that the DM is allowed and-or expected to make those restrictions, thus don't assume everything in the books will be open for you to play.
Otherwise, the DM making restrictions comes off as the bad guy, every damn time.
But, as I have said before and gotten flack for doing so, "limitations breed creativity" is wrong. It should be "good limitations breed creativity". Or "constructive", if you don't like "good".
Thing is, not all limitations have a 'good' or 'bad' element to them. Oftentimes they just are what they are, as forced by external circumstances.
Example: I wrote/played music with some people for a long time, and for much of that time simply couldn't afford the (admittedly costly) gear I really wanted. Result: I had to accept the limitations in the gear I had, and work with that. Doing so led me to some (I think) quite creative solutions as to how to get at least vaguely close to the sound I wanted with gear that wasn't the least bit designed to do it.
In game terms, the DM is the external circumstance forcing a limitation.
Just having limitations merely to have limitations doesn't breed any more creativity than avoiding limitations solely to avoid them.
Here I think it depends on just how creative folks want to get and-or how much effort they want to put in in their attempts to end-around those limitations. Unlike my music example above, it's not a question of (the equivalent of) affordability.
The DM says "No Rangers in this campaign". If I had a Ranger in mind I could either accept that and play something else or I could use the classes and options that are allowed to build something as Ranger-like as possible.
Personal example: 3e didn't have a separate Illusionist class, but I wanted to play a 1e-like Illusionist. I put a lot of thought and effort into how I could use what 3e gave me to build the nearest equivalent, and that's what I played. In replicating a 1e Illusionist the experiment wasn't a smashing success, but as a character she was lovely!