Tobar said:

His entire life Luke wanted to escape that planet. And after seeing the people who raised him brutally murdered there, he swore he'd never return. Only to be forced to in order to save Han.

So deciding to retire there doesn't make a lot of sense for him. So if that's the reason we go back there it's incredibly weak and a sign of lazy writing.

A lot can change in thirty years, including Luke's mindset. If one is going to isolate themselves and commune with the Force, it's a slightly better place than Dagobah, and there's civilization around if one craves company.

If Obi Wan left something important there, it had better be well hidden, as his house was probably looted long ago.