Cool idea, I like the intention and the background for it. I think the primary issue is that this doesn't necessarily align with how the game modes are developed.
These suggestions fit well into a milsim game, but I don't think they fit well into the way that Battlebit is developed and played. The appeal for many players is the arcade action and chaos.
-Assets like barbed wire, emplaced machineguns, watch towers, are not things the devs have done for any other map. Some of this would likely require retooling assets, or making new once from scratch.
-Standardizing the map size is probably more difficult to balance than what they've done already, and even if they could balance it, it would risk making all maps feel "samey"
-defender tickets is realistic, but does not necessarily align well with the pace of the game. Getting people to play defense is already difficult, and even when people do stay back on defense, a good transport helo can usually wipe a point in 2-3 drops. Additionally, in the real world attacking forces get tired, scared, and don't respawn. In a game like battlebit, there is no tired or fear of death to slow down an assault.
-Vehicle balance has some nice ideas
Also, many of these ideas are based on an assumption that the invaded force is not a peer power, which is not the case for battlebit. It's two military super powers fighting.
I like a lot of these ideas, but I think that the concepts you have in here fit better in a title like Hell Let Loose or Squad.