De Gea
Rojo, Jones, Smalling, Blacket/ Evans,, Shaw
Mata, Blind, Di Maria
Rooney/ RVP, Falcao
Van Gaal generally has adapted his formation to his sides but the philosophy remains the same. That formation would have 1 key weakness though. Falcao cannot play as a lone front man, Colombia tried it and failed, Atletico and Porto also put a partner with him. He needs a partner so it would be him and RVP up top.
Van Gaal will never switch back to this system...
There's no real leader in that formation though...Swap Januzaj for Rooney
LVG won't change the formation. You will have 3-5-2/5-3-2
GK - De Gea - easily our best keeper and definitely good enough to be a starter.
RB - Rafael - is naturally a right back, unlike Valencia and I rate Rafael, but his fitness needs improving.
CB - Marcos Rojo - experienced at the top level and probably one of our better centre backs.
CB - Phil Jones - good, but needs to run at centre back. Either him or Blackett.
LB - Luke Shaw - has Premier League experience, but none in Europe. Marcos Rojo if not him.
DMF - Blind - is probably best as a defensive midfielder than a left back and probably our best one.
CMF - Ander Herrera - obvious, because Carrick only had one good season and Cleverley is Cleverley.
RMF - Di Maria - easily our best winger and you'd rather play a player of his quality in his best position.
AMF - Juan Mata - Its his natural position and Rooney is best as a striker.
LMF - Januzaj - better as a winger than Rooney and better than our remaining options.
CF - Falcao - better than Rooney and Van Persie. All can't play in their preferred positions at once.

Its clear you love Januzaj... but... really? in front of Rooney..? ;-)
Can't really leave out your club captain, can you?
Mine is a little different than I assume most will be:
http://footballformation.co.uk/team/4231/020914204245.png
I put Valencia instead of Rafael purely because our defence is too small, they average 5ft 11 with Valencia . . . which is still pretty small.
my reasoning not including either RVP or Rooney is because we need to pack midfield, with such a frail defence and no real box to box mid, our best bet is numbers.
Herrera and Blind can play a holding role well, with blind sitting back and Herrera advancing play.
Di Maria would play more down the wing, where as Januzaj would play where he is best, running at the defence and taking people on slowly but surely, rather than out on the wing where he is less efficient.
Falcao plays best alone, and he is, painfully to say, probably our best striker now.
What would your team be?