We have introduced connection string option to control where are statements prepared at connection level. But It's unlikely optimal, it would make much more sense to do for individual statement.
The driver conforms to ODBC 3.8 specification, and it allows drivers to have among other things driver specific statement and connection attributes. Independence from the data source is one of the greatest values of use of the ODBC, and use of such attributes won't cause the vendor lock, i.e. dependency on concrete ODBC driver. If application sets these attributes with other driver, it will simply get the HYC00 error "Optional feature not implemented". If the driver manager does not support ODBC 3.8, it will return error about unknown attribute HY024. In any case the application should simply ignore the error(or process it in some way but not to stop) and using of these attributes with other data sources will not have any bad outcomes, while improving performance if used with the data source they have been designed for.
At the moment we need to have 2 attributes - one to make SQLExecDirect to use SSPS/binary protocol, and second - to make SQLPrepare to use CSPS/text protocol. The attributes should be possible to set at connection level(e.g. to prevent changing them by connstring option or force to change default). EDSERVER and PREPONCLIENT options should set default values for these new attributes.