1. Say you kick a football, well... ball, it can go straight, but if you kick it right, the ball will have a rotation. That rotation will cause the ball to fly on a curved path. Substitute for a luci-shot. Not a big curve, a small one, like 5-10 degrees max, so you can't shoot around the corners. A "pro" trick (like strafe-jump, or a super-jump) not a "easy to do for mediocre players and for ATCS tunnel spam"

2. A luci-ball can have 250 maximum charge (damage wise). Say, you can charge the luci to 300-350, but above the basic 250 the more you charge it, the slower it goes. 250 is enough to kill any alien structure besides OM anyway. No unlimited charges (one-shot OM kill), or even set the max damage to alien structures to 250. Sure it is powerful, but the camp-rant can doge it easier. Actually I thinkg this is a bad idea, afterthought, but I'll leave it anyway.

3. Think Shotgun reticle. At certain distance all of the shotgun pellets (semi-random, set by a bitmap I think) hit inside the round reticle. The luci-shot always hits inside the round reticle, but it might hit a little bit to the left or right, up and down. The luci-shot will ALWAYS fly inside a cone, but the further it goes the "wider" the cone gets (like most cones do ). You will hit that mara at close distances, you will hit that goon/rant at medium/semi-long, but spamming luci-balls on bigger maps will become almost useless against alien structures (its almost random against aliens anyway at longer distances).  Long distance is "Transit human default base to the bottom of the stairs" for reference.

4. You charge the luci to 250. You shoot. The luci-ball retains its damage power and splash radius, but as it flies it gets smaller (same Transit-like distance). Now you actually have to aim a little bit better for spamming luci into alien base.

5. The "teambleed damage" you deal to other players is reflected to you 1:1 after a mandatory 1-2 second wait time. If you bleed on purpose after 1-2 seconds, you get punished by the game not the player.  All depends on how often a random, not deliberate teambleed is occuring.

I think that these suggestions are suitable for mods, not for default game.

1. I saw this in some movie, interesting thing.
3. Luci shot is one energy shot, so it should be still same size with one center point (but of course it is game, everything is possible).
4. Well, luci shot is not big, only looks like big. If it will have same damage, then this will be only visual change.
5. I was thinking about it too when I was playing on funserver and someone else even implemented it on some server (without that 1-2s delay). It can punish good players, when you start shooting near buch of players and it can cause weird deaths - player can shoot from secured base, but suddently die, because he killed someone on the other side of map Anyway, it is good thing against teambleeders.

That would drasticaly change the old face of trem, I would prefer not to change dmg of weapons at all.

Team bleed happens, and I don't think we should punish players for it, as there is no way to tell who ran in front of who and how badly the shooters aim is.
But punishment for teamkills can be monitored easily. After a TK or two, a player should be warned/punished accordingly. (And make their punishment method a changable setting?)