What I can tell you, neither I like Arabian Nights or Portal 3 Kingdom flavor setting, but I simply don't care if people like to play stuff from these sets, gameplay is more important than flavor purism for me, people will get used to it, because seriously is not that of a big deal if not for the maniacal vorthosian purists and thats it.
Its more a thing of how often you see it.
If you can overlook it fine, but if its still annoying it takes away from the game.
As it is, its rare to see Arabian Nights or Portal cards at all and even if, they look like normal magic cards and its not particularly invasive.
If you put silly stuff on cards that changes quickly.
Doing so in a "silver-bordered" environment is perfectly acceptable, as you can more easily make a cut for a format, so people that dont want them can enjoy it without , and others allow them.
As these cards are just legal by default it has a couple of issues it piggybacks on, which are entirely unnecessary and forced.