Is the Glock OEM 4.5 minus connector a reasonable change-out on its own?

[Speederlander]

Polish and angle change which reduces the trigger pull weight by several ounces and smooths it out slightly.

Any reason to think it is less reliable than the pure OEM?

[JBP55]

Any reason to think it is less reliable than the pure OEM?

No.

[YVK]

One more question actually, will a gen 4 work in a gen 5?

As noted above, it does. Funny thing about it that I personally don't like it in Gen5. Even funnier thing is that @GJM came to this conclusion too, independently. This is, obviously, a very personal thing but to me it feels as too long and too rough of a roll. I also don't like Taran Tactical connector, which I consider a closest to OEM "-" aftermarket connector, in Gen5. I like both of them in Gen3 and Gen4 guns though.
I use Ghost for my gaming Gen5 and it feels like a very long roll but much smoother. For carry, I think that the OEM dot connector really gives a nice feel and break, and if I needed a lighter pull, I'd just use a 5 lbs striker spring.

[HeavyDuty]

I have OEM minus connectors in my Gen4s (and my sole Gen2, a 21) and prefer them in those guns to an unmarked or aa dot. However, I’ve found my two Gen5s (a 26 and a 45) are perfect as is with the connector they shipped with - I tried a minus in the 26 and dropped it like a hot rock.