Think we will need to manage him carefully over the next couple of weeks. We have four matches in 10 days, including Chelsea semi, so Matic will need to have his games planned ahead.
The fact that we have to manage him carefully (i.e not playing him 3 matches in a row in a span of 7-10 days) and plan his matches could actually be a blessing.
We can play either Fred or Scott and scrutinise if they are disciplined and good enough to play that third (DM) position. Plus, if you are a midfield player, wouldn't you want to play with Pogba and Bruno too? Although you will have to cover a lot of ground for the guys behind (Maguire, Lindelof and De Gea).
I am pretty sure the contract is a 2+1 year as we always seem to do a +1(optional) for all contracts with the player regardless of it being a new signing or an extension.
So, all in all, it is a good extension.
This gives ample opportunities for other midfield players (specially Fred and Scott) to prove themselves and also enough time to the Club to seek out a proper DM player otherwise.