Currently part of what makes holding cades impossible is trapper boiler but also the fact that squad engineers literally never can have enough material to finish a place, meaning that Req has to spend every drop of their points on metal and pray to ASRS that other good things come up.
This gameplay for req is shit, they need more choice and control in what they buy.
This gameplay for building engineers is CURSED. Every squad engineer can confirm that starving for metal and being unable to replace a single trashed and paper thin cade is so fucking unfun. It's worse when req decides they want to do ANYTHING OTHER than spend points purely on metal and plasteel because then the FOB is unfinished and just... awful.
An alternative is that squad engineers could claim miners or some kind of computer that while powered generates points for req to then buy more metal and req actually to not be utterly starved at all times. also gives reason for marines to hold anything other than FOB