If I were stuck owning ONLY what some company was selling (because their marketing group felt they could sell enough to get a payback on that particular configuration), I'd own far fewer firearms, and enjoy shooting far, far less.
AR triggers are a bit of a different beast. They're generally true packs, as in everything is all inside one self contained fiddle-proof package. Everything's fitted and tested at the factory level and it all drops in as one single contained unit. Quite a bit tidy-er of a package than replacing all the guts in a Glock. I feel substantially better about AR trigger packs than I do about Glock, S&W M&P or XD's and the like.
If you've done trigger jobs or replacements on Glocks and AR's, it's very clear to see the error in the above statement. Not all AR triggers are self contained, and it's no more difficult to install or tune a Glock trigger than an AR component trigger. Barring the few places where "tolerance stacking" can bite a guy in the butt on both Glocks and AR's, Glock aftermarket triggers typically go in and function fine after a 5-10min job. Take down as normal for cleaning, push out two pins, pull out both blocks, twist the trigger bar out of position, unhook the spring, hook on the new spring, twist the new bar into position, slide the blocks back into place, replace the pins, and function test.
Alternatively, there are as many or more (I'd personally bet considerably MORE) AR-15 triggers on the market which are NOT self contained units than those which are. Just off of the top of my head: CMC, AR-Gold, Velocity, Timney, Wilson, and Lantac do make self contained FCG modules, but Geiselle, Ruger, LaRue, Stoner, Bushmaster, Rock River, JP, BCM, Hyper Fire, LWRC, and Jard all make traditional component enhanced FCG's - not to mention every Tom, Dick, & Harry making a conventional mil-spec trigger which isn't self-contained. AR-15 triggers are hardly standardized for self-contained design. And AR triggers are no less vulnerable to "tolerance stacking" issues than any other firearm.
Having done my share of work on both designs, I know I can install a Glock trigger faster than any of the popular non-self contained AR-15 triggers listed above.
Most people don't REALLY understand how either action works, but the AR-15 fire control group performs a lot less functions, and the safety easier to visualize. The Glock triggers and trigger bars do incorporate more safety features than the AR-15 trigger, and unlike the AR which reveals its safety function when the upper is removed, the Glock safeties only operate when the two are assembled and the FCG is essentially hidden, so that lack of understanding will lead to more opportunity for mis-fitments to cause function issues which go unnoticed in the Glock design. Guys slap stuff together, pull the trigger, and it goes bang - all the while, they can't tell the drop safety isn't engaging or the pin block safety isn't disengaging, so they think the install was successful. An AR is more transparent about giving away FCG issues, if it goes bang, disconnects, resets, and DOESN'T go bang on safe, it's done properly. A Glock FCG isn't so easy to function test.
In reading this thread, but risking a guess without seeing the pistol in person, I would assume the cruciform on the trigger bar needs a little more bend - little more engagement on the striker bar (more sear). That angle dictates the security of the drop safety.