I'd probably give the one with the least restrictive rule set (for resistance training) the edge.
I think you are quite right about resistance training improving martial arts skills. In some aikido training, this is all but ignored. In many martial arts, resistance is regulated in detail, or very limited in some way.
To learn martial arts, one must try to understand the dynamics of attack and defense. Normally, both combattants are attackers and defenders throughout.
Again, I am reminded of Musashi's Go Rin no Sho, where he says about the feared bandit hiding in a house that the people outside are afraid to enter. They should realize that the bandit is equally afraid of them.
In aikido, many uke have the wrong attitude in attacking, because they exclude the possibility of tori attacking them (with anything other than an aikido technique). So, they position themselves vulnerably, or sometimes they resist in a way that would hardly be done by somebody alert to the possibility of tori forgetting about aikido and striking instead. And so on...
Nevertheless, in aikido the goal is very different from defeating an opponent, so the above is of limited significance. I'm just rambling