That is a hardship to children of the 3rd world, which I would not visit upon them ...for two pins, I would fire this stuff up into the outer ends of the universe... but that is not current policy
Bono needs something new to get upset about
And if you fire it off into space some aliens might find it; this would probably be considered a declaration of war
4v4 tends to have significantly higher resource income, initially because 4 players have more capping power so more points get capped faster, later because almost all points will get cached up sooner or later
This tends to mean that teching is faster and that there are more vehicles on the map
2:
Game Length
Because 4 players are harder to drive off the map and kill than 1, and because of the higher resource income, comebacks are easier and it is harder to win a game in a single offensive. As such games tend to be longer.
This means that large late game units and abilities with high CP values are more likely to come into play and you can afford more of them
3:
Map Size
Greater map size makes it slower to get back into action and benefits factions with forward retreat points.
eg:
USF Fast MAJ is often more important than getting CPT tier or any light vehicles
4:
Rhythm
Because of the higher resource income in 4v4 build orders are different to 1v1. There is also the issue that in 1v1 you cannot specialise so much, you cannot for example rely on your teammates for hard AT and tech through without building them
5:
Tech and Strat decisions
As resources are plentiful, teching is fast and the game will probably go to distance you generally want to get the best units you can as soon as possible.
Intermediate tech choices such as going P-IVs had better be something that wins you the game, or they will be out-classed later on.
Kaitof has observed that 4v4 often comes down to making most efficient use of your pop-cap than anything else
Further the fast teching often out classes medium level call in vehicles, going mobile Defence and getting a Puma at CP6 loses some impact when Panthers and Shermans can hit the field at CP4 or so
There's also synergistic strat decisions through picking complementary commanders
6:
Different Units
Not just because of all the above, but also because in 1v1 you only have to worry about one opponent and what he might do, in 4v4 there are 4 opponents whose units can threaten you
As such fragile units that require careful micro, such as snipers, have a short life expectancy in 4v4 and don't get used that much
7:
Different Skill Sets
4v4 involves reading the game, observing 7 other people and what they are doing
1v1 only needs to focus on 1 opponent and control your own units
For this reason 1v1 skills in micro translate better into 4v4 than 4v4 skills help in 1v1
Conversely though 4 people who try to play a 4v4 as 4 1v1s will generally lose to people who play it as a 4v4
8:
Balance
Late game comes faster and lasts longer, so the balance in 4v4 is more heavily focused on late game where Axis have the advantage through better Vet (OKW) and better tanks