well, dummy effects that hit creatures can be scripted with SD2 (if they would depend on more complicated states, like instance data)
ScriptEffect spells can be added to database scripting (which doesn't always work, because they often have random effects, or some conditions)
But regardless of where dummy/script effects should be implemented (database, sd2, core, new-scripting-system), the main problem that is really slowing down, is to know _what_ must be implemented.
Hence I see no big reason to create a new system to implement them easier, when the only problem is to know what to implement.
Creating some additional hooks for SD2 to be able to "script" target-selection, effects, and similar is indeed open to discussion.
However an easy interface to implement unique things might slow down the process of figuring generic solutions