He will almost certainly regress further if he's on the bench here for another year. LvG is quite rightly not prepared to risk the interests of the squad as a whole to experiment with Januzaj when we have players like Mata, Herrera, Fellaini, and Memphis in the attacking mix. If LvG doesn't feel he's quite ready then he needs to go on loan rather than sit on the bench or play with the reserves.
We should base it on the latest preseason where Perreira was clearly the star in terms of emerging youth talent. What Januzaj did for a few games under Moyes is ancient history now and the fact that he hasn't been able to replicate it speaks volumes about how ready he is for more first team minutes.
It's not like Januzaj wasn't doing really well in the preseason. The one game he played centrally, he was constantly creating problems (and got a goal as well). Besides, you can't completely ignore what he did under Moyes. History or not, it's still a reflection on his quality.
I'm not as concerned about Perreira because he still has that time of being in and out of the first team left to do. Januzaj did all of that under Moyes and LVG last year. It's time to start giving the boy consistent starts and watch him shine (or fail? who knows. but it's a certain fail if we don't do anything).
Yes, he'll definitely regress on the bench but he wont be making any steps forward by going to Sunderland of all clubs. The thing is, I don't think it's a "risk" or and "experiment". Everyone knows he has the quality so why not just unleash him.
If he plays the league games, cup games and at least some of the PL games I'll be happy to a certain extent but as it stand he's not even being selected to be on the bench. That just frustrates me. Honestly, I feel like LVG doesn't rate him; maybe he's not versatile enough for him or doesn't fit into the philosophy? I have no idea.
To sum it up, I rate Januzaj really highly. If this was any other hot prospect I'd say okay, a loan is probably the best way we can go on about this. In Januzaj's case I well and truly believe he's a potential world class player.