Once is a bad limit if there are "bad" islands. Just make it twice, lots of things work on a day vs night basis. Like a regular tour and a night tour or whatever.
I honestly dont mind just a limit on one. Considering we have so much new content to explore as well as the island travel, one limits you getting bored of the islands so quick.
I'd have liked it to be maybe a limit of 3 times, means if one or two islands are rubbish then you might have the chance or finding somthing good on the 3rd, am not sure how to feel about it being 1000 miles as well, maybe 500 would have been better, I don't get to play much so there would have to be some time travelling with trying to save up some miles, am hoping once I have all the new stuff I won't need to go as often
My only concern is a bit different, let me explain why... I have two switches in my household, two with ACNH - and after update me and my GF playing together in the same time. We are starting travel to Kapp'n same time (literally) - and as far we got only two mistery island, one most probably common, another one in rain. I noticed some minor differences, but I wonder if we will experience same typy of island every single day... if so, maybe this is a reason when we can travel once a day, as it's some sort of mistery-pattern to visit those islands... not so sure.
Anyway I have no problem with visiting those once per day, I can live with this decision - but maybe at some point I will need something special and have to wait a bit longer... but don't mind.
My first island was sunshine, I had assumed it would be similer to the islands with nook miles an it would just be totally random with a 1 in so many chances of having a rare island, will be interesting to see if they do follow a pattern
I don't mind at all. It gives me something to do every day and just like with the mystery islands you can still fish, dive, etc. to make some extra bells.