Would love to see mission locations diversified. Currently, it seems like there are some set areas where missions spawn in, with only a little bit of wiggle-room. This creates a situation where players who have been around longer automatically know the best positions for most missions. In time, this is bound to get boring. I think it would be a huge improvement if missions could also spawn on open fields and clearings instead of exclusively beside roads at specific locations. For example, there's a massive area up north on Cherno, which is completely unused. Just look at the blue circle missions from the good old days of Arma 2 to know what I'm talking about.
Also, having vehicles as mission loot would probably increase the amount of vics roaming the map, which would be nice.
Other thing I'd like to touch is the Black Market Trader mission. Currently, after completing the mission the trader is available for 10 minutes (correct me if I'm wrong), which seems just a tad bit too short in my opinion. Maybe consider adding an extra 5 minutes to the timer? Would be interesting to see statistics about number of completed missions vs a number of times people actually bought something.
Some other ideas.
*KD ratio and respect shown in the highscores instead of max kills and deaths.
*Days survived and kill counter on XM8.
*The heatmap of all deaths is a nice little feature in the player portal. Wouldn't it be cool to also have a heatmap of all the positions you've killed someone? Or an overall statistics of all the players' deaths and kills in a given period?