I haven't much of an idea about how to implement plugin support, but given that code changes from multiple sources have a high potential of conflict, it seems quite dangerous to me.
Well the potential conflict wouldn't be more than what any mod that alters the exe has even what TobEx has. The creator of such a plugin, would still need to have good knowledge of the inner workings of the engine and investigate possible conflicts with (other) exe-modifying mods (and ofcourse with TobEx). The user would still be the one that decides if he or she wants to use a plugin.
The biggest advantage is that modders, in this case me, can implement stuff on a TobEx-level (or engine-level) without resorting to direct byte-patching or having to integrate it into a personal version of TobEx of sorts (which would be a support nightmare).
As for the implementation, I would be willing to write the code and test it a bit. Then you/me/we can release an alpha version or something. The idea is ofcourse that no (additional) changes (to the engine) take place unless a plugin is loaded.
P.S. Things I'm currently investigating and would be implementing in a plugin:
- Shared Identification: Checks the entire party when determining if an identification spell/scroll/item is available. Avoids the need to shuffle items around each time you need your mage/bard/someone to identify an item.
- Multiple Launchers: As mentioned before would allow you to equip multiple launchers of the same type.
- A few other minor stuff.