I'm new at the Forum.
So, my greetings to you all.
It seems to me that a nice simple feature as a slide lock, unlockable via slide reward pull, would be a plus to the R9.
Another nice feature would be an automatic slide release when a loaded magazine is inserted in to the weapon.
I have a 9mm H&K USP that automatically releases the slide when I insert a loaded magazine into the weapon (of course that the slide must be retracted and holded on the catch and I must slam tha mag in).
Some say it is the slide catch that is worn out. I love this feature.
R9 could do the same, except that it shoudn't require slamming the mag.
So, fast reloads, and no bulky slide catch release levers!
As for the magazine release, just keep it the way it is.
But the mahazine should have a litle tip as the Walther's P 38 to help extraction.
This way one could use the Walther P38 user's trick: Just slam at the base of the magazine, in a rear movement, with the index finger of your support hand, at a 90º agle (just forming a hook with your finger at a horizontal level).
This way, the mag releases enough in order as to be "hooked" down at it's front and gragged down untill it falls.
These two movements may be perfomed in a split second.
Now you shoud have a reward locked slide, and a R9 ready to be reloaded.
Hope this helps.
Kind regards from Portugal.