I think he will be a great player.
BUT I also think that people are reading his hype a little too much, bar Pocock 7s never really dominate that young. Pocock, as the obvious exception, only got good by about 20 but that's because the Force were willing to give him a bucket of gametime. Liam isn't even 19.
Also, yeah the kid has clearly gotten better as a player and is looking bigger. But, just because a website says he's put on 10kg and he looks ripped does not mean he has a man's body, in fact it means almost nothing. Website statistics on athletes (even official ones) are notoriously wrong and the fact he looks ripped could have as much to do with skinfolds as actual muscle mass. This isn't saying he doesn't have an impressive physique but Rome wasn't build in a day (or an ONE off-season).
Once again, I'd like to say that he WILL be good but don't place too much expectation on the young lad too soon.