One of the first exposures I had to an ODBC driver was NOT a good one - the particular behavior for ANSI NULLS ended up causing some issues in a database application that I had inherited, so I tend to keep my eye on these things. Mind you, it was back in the SQL Server 6.5 days, and I haven't had an issue since then, but I keep an eye on it nonetheless.
Windows 7, which is set to release soon, includes a new ODBC driver - 3.80. It gives you several new enhancements which you can read about here, but keep this in mind when you're deploying a new operating system - this is exactly the situation that bit me. The point is, as always, whenever you make a change, test, test, test.
This article is talking about a new ODBC driver manager, rather than new ODBC drivers. In fact it mentions that none of the existing ODBC drivers use these features and that there are no new ODBC drivers yet.
Was the situation you refer to in SQL Server 6.5 caused by a new *driver* or new driver manager? Or did you actually have an ODBC-related problem with the new driver manager (I couldn't really read enough into the post to determine).
I did see an old KB mentioning that there was a problem once that was caused by a new driver manager, but these are fewer than those reported against specific drivers.