I think this is a pretty fair trade for you guys as well as NYR. For NYR, Lias just wasn't going to work out here. The relationship was pretty much destroyed and while they did salvage it to some extent recently, it was best for both parties to move on and start fresh. To get a 2nd (even if it's a late one) for him is pretty decent value all things considering though it doesn't seem like the Rangers made the best pick with it.
For LAK, I think it's a good risk for the Kings to take on someone who I think can be a solid 3rd line center if things pan out. He's obviously further ahead in progression than someone you'd take at that point in the draft and probably has a better chance of panning out then someone taken at that point in the draft as well. He's a very emotional kid as you can tell and hopefully he's learned to harness it a bit after this whole ordeal. Something happened which we haven't gotten the full details on while he was in New York/Hartford though he also recently accepted a lot of blame as well. He said he was staying up late so he could play video games with friends back home since he was so depressed here. It also didn't help that his 1st season after being drafted he played a ton in many different locations (Sweden, WJC, Hartford, NYR). 18-19 season also saw him bounce back and forth between Hartford and NYR. 19-20 seemed to be the breaking point as he had a really good camp where he stood out and clearly earned his spot but he never got off line 4 even for 1 shift (Brendan Smith even got a turn at wing on the 3rd line). He was stuck centering Haley and Smith for the most part which is a no win situation while Brett Howden got the 3C role though many people thought Lias earned a bigger role in camp and Howden didn't deserve those minutes. To me, it was clear he wasn't a David Quinn favorite but why is a bigger question. He routinely got limited minutes in that 4th line role so who knows if maybe it was a practice thing or maybe he just never earned Quinn's trust. He was sent down shortly after the beginning of the season and went to Hartford and that's when the issues started occurring and he was home by Christmas. It should be noted though that even after his good camp, he did himself no favors with his play on line 4. So while at some point he probably should have gotten 1 shot off the line, he didn't earn it beyond his camp either. Again, don't know if it's a byproduct of who he played with, maybe being upset about the situation, or both.
He comes across as a smart/cerebral player on the ice though the biggest issue to me is his skating. I know someone above said it wasn't a strength but not an issue at the same time but I can't agree. It seemed to have a big time effect at the NHL level and was definitely a hinderance. Like I said, I think solid 3C is definitely a reasonable and attainable goal for him but not sure if there's any more upside there especially if he doesn't improve his skating.