This will not only help in the response time of magento especially under heavy load but it is important to get done in the beginning, so that modules support the master / slave concept of replicated databases.
For those who don’t know, a replicated database is when there are two databases, where one is the copy of the other. The advantage is that reads can be spread across two or more separate databases. In order to support this magento would have to differentiate between write and read queries and then load balance reads between read servers. Also, it would have to be smart enough to know when to read from the master. For example
update product set name = “new name” where id = 1
select name from product where id = 1
May not return “new name” because the slave server has not received the changes. An quick and dirty way to handle this is set everything to read from the master except the product catalog. May not be as scaleable, but by far the most mysql intensive aspect of magento is searching, the product catalog, and product display pages. All of which do not need to be up-to-date by the second.