One thing I forgot to mention in my initial post is that I find there's a higher level of wind noise audible in the Mk2.5 than the Mk1.5. It seems to me that less attention has been paid to closing up the panel gaps. In fact I get the impression that a lot more thought and attention to detail went into the Mk1/1.5 which was a complete break from anything that had gone before. It seems as though these days they just draw something that looks pretty on the computer without giving much thought to practicality. The Mk2/2.5 and it's successors look like just run-of-the-mill generic cars as has been said. The loss of the high-level rear light clusters on the Mk3 has finally removed all trace of the distinctive Focus styling.
There's also more road noise in my Mk2.5 although that's probably due to the fact that it's just a Zetec while the Mk1.5 is a Ghia so the sound insulation standards are likely to be different.