New to airsoft and only played one milsim so far (Black Site) but wanted to share my experience with the DMR and sniper role. This is coming from a player filling a standard rifleman role.
It's always possible to improve the ruleset of the game to be more enjoyable for everyone , but I do feel that the DMR/snipers that I worked in close proximity with were utilized to their fullest. They were crucial to penetrating enemy lines and pushing forward. In many cases we were able to combat enemies that had high ground and/or outranged our standard riflemen by calling for support from our DMR/Sniper units. Without their support, a lot of engagements could have been turned into stalemates or losses altogether. Set winning the fight aside, a stalemate in airsoft where neither group can quite get the range to make good hits kind of ruins the flow of the game and feels more like a paintball match. When I'm paying so much to attend an event like this, I really want the whole milsim package. I think these events would lose some of their luster without the specialty roles.
I think it would be a huge mistake to remove these roles from gameplay. If the talk of removing these roles is safety related, I'm sure there are restrictions that can be put into place without handicapping the performance of the rifles. I'm interested to see why this is a possibility.