I don't like this direction - I prefer a more flexible system in terms of slots than random loot, but much weaker power to compensate, rather than having (almost) the same list of effects in exactly the same slots as random loot, but I can understand it's a viable development decision to make, even if I don't like it.
Given that, I agree with you that at level 30 there's a reasonable balance between a guaranteed good combination (at high ingredient cost) for Cannith Crafting but the potential for notably better random loot, because there's a 6 level difference between Cannith Crafting (34) and Random Loot (40... at the moment until higher level quests get released?).
At EVERY other level, Cannith Crafting and Random Loot are the same level. Assuming you have the ingredients, then aside from finding crafting more boring than questing, there is no piece of Random Loot you would ever use over Cannith Crafting - the chances of finding the right item, with a bonus slot (and probably an augment slot as well, because why wouldn't we use an item with an augment slot for all Cannith Crafting?), masterful craftsmanship, and maxed rolls on 3 effects and exactly the 3 effects you want at exactly your current level is so miniscule that you can just forget it.
Please, devs, don't forget all other levels. Like warlocks and everything else, it's not enough to see if it looks okay at level 1, and level 30, and just assume everything in between is balanced, because that's just not the case.