I have been wanting LiF:FV for months, and I finally bought it the other day. It's good, I do like it, though I find some of it cumbersome, and needs a better knowledgebase, and a better tutorial, but a lot of games are this way.
I have been playing Wurm Online for over 4yrs, it's a similar concept to Banished & LiF:FV, you need to settle, build and has the bonus of a highly active community, PVE or PVP events, and it's a subscription based model with active development. No modders, as it's a hosted game.
As we don't know what source code (if any) was used from Banished, or even if it's been borrowed, or licensed, it's a dangerous game accusing devs of copyright when it can't be confirmed that they are.
The game has so many similarities to Banished, but so too to Wurm. One could argue that each are taken from even earlier games.
The problem with these accusations, is that it doesn't help grow gaming communities and encourage developers, yes Luke has built a great game, but, let's be honest, he's rather made it 'abandonware' rather than an ongoing platform, my loyalty to Luke, Banished and the community only goes so far as to the game itself. The legalities of other games, unless proven one way or another, is of no consequence to me either. If I like the game, the genre, the platform I will invest in it. If it turns out that the game uses source code that has been stolen, borrowed or selectively taken, then I will simply request a refund and go on my way, until then though, I play it.
I guess the only way to prove it one way or another is to be access the source code, compare to Banished and submit the findings to Luke to follow up.
So, in the meantime, if you like the genre, like the look of it, I'd say go & buy it and enjoy it. It's good, but needs some finetuning, and as an early access game, it's been worth the money I spent on it. I've spent money on worse, for more.