Overall it's a nerf I would say. The commander isn't really munition's heavy since there is no offmap if you don't count the HT flares that nobody uses so using munitions for the upgrade doesn't hinder the commander all that much. The repair speed is the main draw of the upgrade and you aren't going to need satchels very often at 0-1 CP or want to waste munitions on using them at that point of the match so that buff is pretty much useless in exchange for losing repair speed when I've never seen anybody complain about Pioneer repair speed with the upgrade.
Imo risking a 200 manpower 30 or 30+30 or 30+60 MU to use satchel is to high of risk and I would rather see the upgrade cost removed.
Maybe one could change the name of the upgrade to "advance repairs" and have it provide the repair bonus and have the rest come without the upgrade.