Having thought about a moment, let me take a better shot at explaining why this is a poor idea.
Q: What is your goal in the early stages of a Diplomacy game?
A: To pick an unfair fight, where you're on the winning side, and ideally where you get most of the spoils.
Q: How do I get most of the spoils?
A: The easiest way is to be the second power into a 2 on 1, and to jump in right at the moment your target has sent all of his forces to the other border.
So, there are two problems. The first is that just as you are answering these questions, so is everybody else on the board. You are committing first, and committing so hard that it's the answer for both England and France to the question of "how do I find a 2 on 1 against a vulnerable enemy" has an easy answer. And you don't like that answer.
The second is that you are committing first, which means that you don't get the biggest share of the spoils. A fair fight between G and R means both lose. In an unfair fight, well, who's your ally? If Austria, you're not going to end up with both War and Mos, right? Either way, you don't get Sev. And if England has chosen to work with you instead of attacking you, you don't get StP. So your best-case scenario here is that you have given away Holland and any claim on Belgium (let's say you've give up 1.3 centers, but it's probably a little more on average) in return for Warsaw and Sweden.
Basically, the opening stages of a game are always a scary time, where you're trying hard to find an ally instead of being on the wrong end of the 2-on-1. I strongly suspect that openings which allow you to look at the board before being forced to pick an ally fare better than openings which immediately commit to an enemy, simply because having two possibly allies to pick from gives you more leverage than a committed war where the third player gets to pick his favorite side. After all, if A, B, and C are going to pick some 2 on 1, you start out having a 2/3 chance of not being the loser. If A and B immediately and irrevocably go to war with each other (and this is pretty irrevocable), that becomes 1/2 if you're A or B, although it's pretty good for C...