Forums / Cotonti / Core Labs / Archive / Core functions pluggable

also I think today about pluggable functions/
and I think that rating, comments, parser, pagination must be pluggable
but I think that they must be not look like plugins or replaceble files - they must be something between them.
For example:
folder "functions" in default there are files:
parser.default.php
pagination.default.php
comments.default.php
ratings.default.php etc.

user download and insert in this folder new parser "parser.new.php". And then in admin area he choose parser.

So in this way:
1. this functions are not plugins
2. standart functions we don't need to replace they are only not in functions.php
3. easy to install. easy to choose
4. if user update CMS, custom functions will be not replaced by standart files

what do you think about this?
and i think that in new CMS pagination method must be replaced from sedplus plugin