database abstraction layer

In Drupal 7, as it supports different databases, modules which run queries containing date conversions and comparisons (Views, Date and others) face with bugs connected to different SQL syntax (partially I see a number of problems with MSSQL). Date functions are also a part of SQL and I think they should not be handled by modules. We need a kind of date abstraction layer within database drivers, which will contain date formatting, conversion, and extraction routines. I don't know if current DB layer can be changed too much, but this idea can become a roadmap for Drupal 8.