While I like the fact that maintenance is simplified on the product end, making the MSP cost every single resource just makes the system more complex and inefficient on the manufacturing side.
Take my very simple 2000t gravsurvey ship. It has no active sensors, passive sensors or jump drive to be cheaper. It doesn't require tritanium, neutronium (heavy-duranium armour), vendarite, or sorium, and only requires 5x corbomite for the bridge. I designed this due to a shortage of most resources, and the fact that I wanted the least amount of sorium going to maintenance as possible.
To properly maintain ALL ships now, you now require one world with access to all minerals in order to produce MSP. Any shortage of one resource now means that ALL ships suffer maintenance failures, instead of just the ones that need them. The good thing about the new system is a resource shortfall will have a delayed effect on maintenance, as long as there are MSP stockpiled.
Further, since MSP are used to repair a ship in transit, and shipyards repair in orbit using minerals, are shipyard repairs changed in any way by this? I wouldn't think they are but it doesn't hurt to ask.