Leif needs his shop back, here's why:

[Sicariana]

IIRC, they found stuff about vegatables and cooking when datamining a few weeks ago. Maybe he'll get a shop in the next big game update and be part of nooks.

I think it'd be pretty cool if he got a permanent store to 'expand' his stock thus allowing us to buy seeds if gardening is implemented.

 

[John Wick]

at this point, I just want him to settle in my town so he stops wasting a weekly special visitor slot

That's how I feel about every visitor except Leif.