#2 It breeds unfairness to the small English clubs
Selling clubs always want to get as much money from their players as possible, and this is ideal when there is a bidding war between clubs jostling for the same players. As small clubs are not as moneyed as their bigger counterparts, they will always lose out as the big boys swoop in quickly to tie up deals while the small clubs weight for the latter-day bargain deals.
This perhaps explains why a club like Burnley who would supposedly have wished to sign more players, have only signed one player so far, (in Middlesbrough's Gibson) this late in the window.
Therefore, in the spirit of fairness, the window should have been open to all clubs across Europe for the same length of time to give equal opportunity to all clubs, big or small. This would allow even those who operate on shoestring budgets to fish in the waters most fitting to them, not to make all clubs fish in one small lake that would make some miss out on valuable fish.