The line may be longer but it will move a darn side quicker than the regular line.
As for trouble with room assignments, as I mentioned, if you are not too fussy about where you are, what kind of room you have, etc, it is not likely that there will be any problems. Some folk have a string of requests which are serious competition with Santa's request list: King sized bed, building 3, 2nd floor, not too close to the parking, near to a DSA but no noise from the pool ......

This is going to require a one to one conversation with a CM at check in.
Our request this year is our standard one - not ground floor. And that has already been placed as a request on our booking and can be noted again during OLCI. I am also not too bothered if they can't do it. I may give it a go this year just for the sake of it if someone reminds me - but it will be too late to be of any help to you.
There are bound to be good and bad reports no matter what method is used to check in because it is impossible to honour each and every request.
I say go for it if you are curious or just want to give it a bash - you have little or nothing to lose. If you are having second thoughts and you are arriving after mid afternoon (at the resort), I think it is six of one and half a dozen ....