I carried a Glock 19 for several years in a Blade Tech OWB holster and never gave it a second thought. Wonderful design, and you have three trigger options. I wouldn't carry any gun in a pocket or on the waistband w/o a holster; not so much for safety, but for positioning and getting a full grip on the draw.
Personally I wouldn't add any aftermarket safety. Those PDs that have, or are considering it, are likely being driven by lawyers and insurance companies. Plus, they have varied forces, including some that probably don't like handguns.
I'd get the Glock and a good holster. Your concerns sound like those of some 1911 afficiandos (myself included) who worry about cocked and locked. There are tradeoffs. The Glock is simple to operate, same trigger pull, lightweight, rust resistant.