I know this is an old post, but I wanted to say something about this because this is something that I consider really important.
Nrby wrote:arrows are generally taken a bit into account ... but the way konami thought them up is stupid ... as physical for doesn't fluctuate that much ... mental and technical stats should be the ones that oscillate more ... gray and red arrows are flukes if you ask me that shouldn't exist ... there is no form in the world that makes a player 12% faster on a "good day" ... I personally use arrows just to have a bit of variety so I can rotate some players ... but a red arrow (not to mention the gray one) completely changes a player almost beyond recognition
I kinda agree to some extent with this, but I would say that even though Physical doesn't fluctuate as much, a player can be indeed 12% faster on a "good day", I would even say 20%, the problem is that this is very rare, realistically a player would only play about 5 games a season in this form. Basically the only problem with this is the high frequency that extreme arrows have.
On the other hand removing the arrows is a really bad idea. For example in ML this is really important, and is one of the reasons to play youngsters, because they more than older players, play closer to their potential when on high form, but are not so useful on regular and worse forms. The problem is that is so easily to attain red arrows that you can play with a team full of youngsters almost every game and still win a lot even in the highest difficulty.
Another thing is that there should be separate forms one physical and one mental. The physical one should fluctuate slowly and constantly, and depend on Form, while the mental should fluctuate more rapidly and erratically and depend on Mentality/Tenacity, but still be affected by match performances.