I think a good way to look at this in a broader perspective is to ask "What types of damage exist and how are they inflicted?", go crazy combining them, finally "test" them (whether in the field, court of public opinion, or an imaginary space).
Of course, I'm too lazy to come up with a list right now (I'm on lunch, gimme a break!)... but if anyone else wants to we can begin experimenting. Mwhahaha!
The other approach is to view "improvement" as asking the question "What do you need?" The answers can come in defining characteristics like: legal (!), concealable, practical, effective, etc. Certainly less defined than the first approach, but the contraints can help you think along the "Top 10" lists of Most Effective Weapons, Most Concealable Weapons, etc.
For my part, being in an office, I want a really good
Fighting Pen!
I'm talking a 7.5" platinum (or lead) weighted throwing spike with a tungsten-carbide core (possibly an OTF shiv) and penetrating point and venomous ink! Hmm... is it legal to fatally poison in self-defense?
Now I've just gotta find room on board that pen for a laser torch, micro grenade, and knockout gas/flamethrower! A true pocket protector! [groan]