The sunder rules say you can't sunder armor. Other than that it seems like all the other issues have been properly addressed so I won't say anything else on them.
This is a bit of a tangent, but personally I still don't think using a MW tool for everything is proper. It represents having a circumstance bonus from having just the right tool for the job. I.e., ideal circumstances. For sleight of hand I'd call that a crowded street, not any gadget that I've never heard of thieves using. For knowledge that might represent access to an entire reference library (and time spent hunting through it). For tumble I'd want a springboard floor. Etc. And last I checked I haven't heard of master thieves or gymnasts or etc. using anything else. Not everything is a 50gp tool you can carry in your pocket. Even some of the listed "tools" like an alchemist's lab don't follow that pattern. This seems to me like an area where tweaking and roleplaying come at odds to eachother, and roleplaying should win.