I often see on forum arguments that give a lot of weight to lightsaber forms. And sometimes it gets ridiculously similar to scissors, stone and paper.
I gonna go through each form and give some thoughts about it.

Form I: Shii-Cho
Basically it is very basic form. It is “wild and raw”, which I am fine with.
“In combat, Form I encouraged deliberate tactics, calling for continuous, step-by-step advancement while cutting off the opponent's angles.” – This part is very strange. Whatever style you use, you try to be unpredictable and invent new and random tactics each time. It is not Form that is predictable but its wielder.

Form II: Makashi
Yes, this style is very different as you hold sword in one hand and fight like a musketeer. Considering that lightsaber blade is weightless it makes perfect sense as it gives much more freedom and mobility. This form indeed has lack of kinetic energy as there is less strength in one hand. Should you fail to maintain distance, powerful blow will twist your wrist out. And it is not effective against blasters. It’s like baseball, you can’t aim at ball and hit it as effectively as you would with two hands.

Form III - Soresu
Here is where nonsense starts. Nothing new in terms of techniques in this form. Simple philosophy: defend until your opponent gets tired. With same success you could describe form I practitioner who just happened to dedicate himself to blocking and deflecting things instead of striking. Kenobi is the best example of this style, yet, in fight with Anakin his moves are often just reflection of Anakin’s with exception that he kept moving backward. Before discovering anything about forms I assumed that their style is exactly same but Kenobi as weaker opponent had to be on defensive.

Form IV - Ataru
He hey! We get Form I with acrobatics in between!
“Another characteristic of the form was its fast, powerful strikes from multiple directions.” – Hmm, I thought to penetrate enemies defences this characteristic is important in any style.

Form V – Djem So
It was developed by Soresu practitioners. Ok, they got bored, I am fine with that.
“characterized by power attacks and defense immediately followed by a counter-strike. “ But again, can’t Form I practitioners put more emphasis on strength? It is very natural to put emphasis on strength in any style, unless, it is told not to. If you have strength, you use it. And isn’t defence followed by a counter-strike just another tactic employed in any existing style in order to surprise and defeat opponent?

Form VI
Oh, apparently, author’s creativity is finished by this point. Basically it is just mixture of all previous styles.
“This resulted in a fighting style that lacked a significant advantage” – Ok. What do they mean by that? At any moment he can do powerful Djem So strike, Ataru like jump or switch grip to one handed. Seems like great advantage.
Apparently Sidious, Windu and Yoda weren’t master of all forms, they were masters of Form VI! And imho that is true. They mastered each form individually but then it all merged into one hybrid style unique to them with preference of moves from each style suitable to them.

Form VII
Form VI should have been conclusion but no, author’s imagination has no bounds!
Basically Form VII is Form V, when you are pissed off.
“as many felt that Juyo violated the ‘there is no emotion, there is peace’"
The question is why Anakin is considered Djem So practitioner, when he so comfortably uses anger?
“According to the Sith Lord Darth Traya, the form was both chaotic and erratic, with a heavy focus on offense.” Very same way Anakin could be described during fight. Malice in eyes, lots of power and offence, grabbing throat...
How about Obi-Wan? After Qui-Gon’s death he was offensively and angrily pressing Maul backward with sheer strength and unpredictability.
And guess what? Authors are still inspired. They invented Vaapad! In other words to be master of Vaapad you not only need to be pissed off but accept the fact that your enemy is pissed off and channel all of it into lightsaber. 0_o
I know that all Vaapad believers gonna protest but Forms are called “lightsaber forms”, while Form VII is all about state of mind and emotions and has nothing to do with fencing skills.

Other thoughts
I often see people saying that Dooku lost because Makashi is not suitable against Djem So. Really? Don’t you think it’s kind of lame excuse? Dooku has over 50 years experience and has proficient knowledge in all forms. Surely he learned how to defend against other forms over that time. He encountered Anakin multiple times during CW. If there was particular weakness in his style, surely he would have eliminated it by RotS. Moreover, in his last encounters with Anakin he clearly experienced and had to rely on his superior offensive Force powers. The simple truth is that Anakin because of his potential and talent achieved higher level of lightsaber skill and Dooku couldn’t do anything about it.

Qui-Gon was described as Ataru fighter equal to Windu. What exactly was Ataru about his style? He didn’t do a single acrobatic move, while Maul did the job for all three of them. Honestly, unless we talk about Yoda Ataru is a myth.

“Yoda was master off all forms” – Bah! Yoda overwhelms by powerful strikes imbued by emotion!

Whatever style you learn, you achieve skill by practising. During practice you learn to counter any possible moves of your opponents as well as invent your own moves and sequences. Overtime inevitably you adopt your own style, which has resemblance of the original style, yet, the way you fight is unique.

All Jedi study more, than one form and have proficient knowledge and skill of how to defend against other forms.

The use of kicks and grappling is not part of fencing skill, therefore is not bound to any specific form.

“Masters of multiple forms switch styles to be unpredictable” – Logical if master knows Makashi, switching double-handed to single-handed grip is quite unpredictable. But what is left, if we put Makashi out of equation? Is there any advantage of switching to Form I, which supposed to have no advantages? To Form VI, which is mixture of all others? How about switch between V and VII until you get confused which is which? Switching from defensive to offensive is part of any combat, so it hardly can be called switching to Soresu and back. Sounds cool but those “switches” can’t be traced in any of the films.

Luke wasn’t master of any form, when defeated Palpatine, he wasn’t more powerful either. Entire New Jedi Order did just fine without unnecessary headache about forms.

If we talk about unarmed combat, then yes, there are weaknesses of one style against another and scissors, stone and paper can work. Like boxing versus kicks or punching vs grappling. But with swords it is always sword strike against sword strike, where attacks vary by their strength and angle. It is same type of skill, there simply can’t be significant advantage of one style against another. Yes, there are clever ways of redirecting attacks, counters, faking and all that stuff but there isn’t many. At the end the deciding factor is always reaction, reflexes and precision. When both are on top of their skill, wins either the more talented or as circumstances decide.