talent tree and weapon-related perk used

Hi, being able to customize our perks depending on the weapon we use, for example I play multi-melta with the heavy with the melee perks, but I also play it with the heavy plasma and these perks are useless with I would like to take others and be able to change according to my desires and not have to spend 700 gold each time for the class as soon as I have to make changes depending on the weapons I want to play, this considerably reduces the gameplay options.