Andy already covered the technological reasons why altering the DST period is a Bad Idea™. It's a bad idea that's been done before, but the number of electronic systems today that the change would affect is far greater than the last time is was altered in 1986. Besides the systems that could be changed to the new DST period, there's a vast number of "embedded" systems that simply can't be altered (or it's unreasonably difficult to do so). But why do we have this kludge tacked on to our clock system in the first place?
We change our clocks to shift an hour of daylight from the morning to the evening, for some reasons not without merit. Why not just change from working "eight to five" to working "seven to four" for a period during the year? Oooh, change? Me dink change r bad. Normally, when discussing archaic systems, it's the rest of the world that has come around to doing it the Right Way™, and the USA is still in backwater-mode (the metric measurement system, etc.). However, most of the world is being dumb in this case. Sigh.
Let's take it one step further and get rid of time zones. Time zones stem from a similar motivation as DST: we want our daylight hours to have the same arbitrary numbers applied to them, no matter where in the world we are. Why? No logical reason. Why should it matter if people in Lincoln, NE work from 04:00 to 13:00, while people in Greece work 12:00 to 20:00?
Oh yeah, the 12-hour clock system...that one is brilliant too. Let's make telling time as ambiguous as it can be.
Imagine never having to worry about time zones or DST clock shifts, and knowing that "8 o'clock" always indicated morning (or night, or whatever it always is where you happen to live). I'd call it something like...Coordinated Universal Time. We already have that, you say? Well, crap, why don't we use it?
A decimal time scale would be nice, but I'm not going to ask for too much change at one time.