how sooo
You can only get 5 units in each category unless you make a specialized deck.
However you get far more activation points, more unit cards and higher avaibillity for certain units
(especially recon). Mixed decks got removed and replaced by Coalition decks , specialized decks give you
faaar more bonuses ,earlier timeframes now just give you more activation points and national decks
give you higher unit avaibillity.
I do like these changes though because they encourage balanced deck building while specialized decks became
somewhat more competetive than they used to be.