Easiest method to fix all this is as follows:
1) Reverse the training mode. Training mode will now have two stars. Each star can be removed by beating it in training mode on any difficulty The first star will unlock PVE mode and the second star will unlock PVP mode. By doing this, new Raiders will have SOME idea of what they're supposed to be doing on a map.
2) Create two modes of online play. The first will be PVE mode. In this mode, there are no antagonists BUT there are no extra rewards (This means no blueprints, exp boosts, or extra gold/faction) and the normal rewards are halved. The second will be PVP mode. Rewards are at full with all extra rewards enabled but antagonists are also enabled. This allows people to have the option of antag-free matchs while still creating a high incentive for people to play against antags.
3) Dump the "multiple match" win requirement for rare blueprints. I don't intentionally go for blueprints myself but I can see that as really annoying. Instead, for both XP boosts and rares, place a score requirement of 8 or 9 to get the blueprint.
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Also, a tip for both raiders and antags.
Raiders: I just got 9.0 as Antag Alicia on the Marmalade mission. At various points, I was practically shouting at the screen "COVER EACH OTHER!!!" If you see one of your teammates limping, race over to them and cover. If an antag is on the loose, buddy system. Unless you're playing against an anti-cluster antag like Kuzmann, you should stick close. 1 antag vs 2-4 raiders = antag punching bag.
Antags: Up until recently, I haven't played that much antag but I've come to the conclusion that suicide is a strategy. If they're trying to load a Lyre Sphere/generator/etc with aleph, then don't let yourself get a full 5-count. As soon as you do, cliff jump. It removes the aleph from play and forces them to gather it again. (Alternatively, Huey doesn't seem to understand that killing an aleph-filled antag both wastes the aleph and endangers the raiders.) Suicide Loaht is also an excellent strategy for maps where the raiders have to cluster.