[erpellan]

Some things that I'd love to see as options in rdbms:

Enforced globally unique column names - natural joins on everything.

Throw an exception if a query requires a table scan (bonus points if it printed the statement that would create the appropriate index).

Translate all update and delete statements into inserts (enforced immutable data + versioning).

[bmdavi3]

For queries returning results from a majority of rows in the table, won't a sequential table scan be faster than an index scan?

[jpitz]

For non-clustered indices, yes.

[jeremysmyth]

and if the order is not important. Reordering large numbers of rows can be a very expensive operation.

[moron4hire]

You can force the last one but just dropping the delete and update permissions from your role.