I've been comparing the maximum damage output of each individual tower in different environments. It turned out that Laser Tower did poorly in a majority of my tests given, and here are the reasons:

#1 Extremely situational, yet still weak - I think it's hand-down, the biggest weakness of the Laser Tower, but it's unfortunate how even in it's best-case scenario, it loses a lot of damage potential due to the way it targets it's enemies - It can fire in ANY direction, usually ending up losing most of it's firepower by slightly firing off the road, which is very common.

#2 Poorly justified abilitiess - Here's my opinion on each of them:
-High frequency - Triple damage, no enemy penetration - The penetration is sort of the primary reason why people would even bother using Laser Towers. I mean, would you rather do triple damage to 1 entity at a time or regular damage against minimum 10 entities at a time?;
-Mirrors system - 3-directional laser, 0,5x damage each - This ability makes Laser Tower even MORE situational than it already is, because it has to be placed in a spot where all of it's lasers can do any damage at once. So rather than giving it extra 50% utility of it's damage, it takes 50% damage away;
-Large batteries - 1.5x durability of each laser charge - No complains here, just a straight upgrade;
-Ionization - 50% faster charge, each nearby tower lowering the bonus by 10%, level 10 required - The ability itself is a good upside, however... Is it REALLY good enough to be on a level 10 upgrade? I don't think so.

And now, here's what I would suggest changing:
#A Changing "High frequency"'s stats - Removing the current stats and instead just make it a straight 1.25x damage boost. That or making the damage without penetration a lot bigger;
#B Removing the "Mirrors system" ability altogether - It's a straight downgrade for a weapon that's supposed to do big damage in a straight line;
#C Putting "Ionization" as a regular upgrade, not a lv 10 upgrade - As I said, it's a good bonus, just not good enough to be on lv 10;
#D Adding "Intelligent Aiming" bonus - "Improves the accuracy of the tower, unlocks at level 10" - In other words, it's aiming would be restricted to aim for the center of the block, it's target is on, rather than where the enemy exactly is. That would make laser beams more likely to hit all entities on the straight road rather than just a few, making it's situational usage much, MUCH better.