[Eagle of Fire]

in UFO if a soldier tries to shoot from cover he just shoots every time right into the cover that's just next to him.

That is not completely true. It really depends on which kind of cover you're hiding behind. I particularly remember fences of any kind gave fair shot protection while allowing you to shoot thru it if you were at point blank range. UFO is a very old game anyways, such principles as shooting from behind cover was never even thought of in those days.

I haven't even researched heavy laser since they're worthless to use compared to rifles.

Well, I myself never research the laser weapons until way later in the game simply because I consider them useless coma. However, the heavy version of any weapon owns in term of firepower. You certainly would not want to equip a full squad with it, but you sure need the firepower once in a while.

Using laser VS plasma weapons always been a great source of argument for Xcom fans. Laser weapons are easy to use, available sooner and usually all have auto shot which is a feature a lot of people swear from. Plasma weapon however pack a bigger punch and usually have a higher accuracy, especially with aimed shots. What I do myself at the end of the game is to give all my crackshots plasma weapons (they almost never miss), and give my new recruits laser weapon and hope the auto shot will do it's job.

Anyways, what I always personally do is aim to research medkit then personal armor first of all, then look to get better weapons. No use to have uber weapons if you have nobody to fire them.