For exmaple my ruler has 25 martial and some guy with 15 martias has bigger army than me from one castle/province than me from 4 provinces and like half of the kingdom. I mean that penalties from non capital region(duchy), wheater, heavily recruited and so on should be lowered or reworked. And in this case, reinforcement is non existend even with marshall in province. Those bonuses realy boost little owners.
I don't have this issue ("broken").
If I don't want claimant adventurers to recruit from my provinces, I choose one of the other options (e.g., just pay them some gold). The weather happens and is a real thing, causing the "max" amount of levies in the levy bar to fluctuate, but levy reinforcement is always happening at the same [a lot slower than vanilla] rate. AFAIK (I have changed it multiple times over the years with different patches), there aren't penalties from your capital duchy-- just lack of the crazy bonuses for your capital county, which is why I keep my demesne there.
In general, I don't ever expect all of my holdings' levies to actually be at their absolute maximum no matter what I do. Sometimes one or two is, depending upon how and where I'm raising them and recent weather. The absolute maximum should never be considered to be what's required for "not broken."
FWIW, there are 2 tweaks to related modifiers currently in our development branch that might reduce some of the seemingly random fluctuations. None of them are going to make you have more troops than a guy heavily centralized in his capital if your demesne is scattered all over or recruited from by adventurers, however.