You still need to get the materials, a simple example is 3+ times more. The mat broker will help with the hard to find rare stuff but doesn't mitigate the quantity.
And the first G5 efficient MC is fine, but for every new MC you want to mod the new system will cost you 33.6 mats (on average) vs ~9 for an acceptable roll under the old for us casual players.
But you already have the materials. Through regular gameplay you come across a ton of junk which in the current iteration of the game only clogs up your limited mat storage. The difference will be that with the mat trader and per-met storage you will have an incentive to pick it up now, to both craft the initial low grade mod and to convert into higher grade mats.
Also, I must remind everyone that the Engineers were never supposed to be a feature you use all the time on all modules of all your ships. Engineering is supposed to be something special which takes some effort. Not every one of your ships needs that grade 5 DD or a 45ly jump range.