Because you dont have the enhanced recipes you're tied to the crafting limit so these factories aren't that useful VS the original mod.

The craftable aspect I really like the idea of but not having the recipe to go with it makes it pretty useless when your tied to no more than 60 crafts a second

The big recipes have their own drawbacks though, like cluttering the interface.

There's a lot of settings you can tweak. If you reduce the size and speed modifiers, and increase the spawn rate, you should be able to achieve a better throughput simply by using more factories for the same recipe.

The original mod has code in it specifically to keep "big recipies" to only show when interacting with the big factories, there's no where else in the game you can view the big receipes and they don't show in the main interface or for other factories or the player.

A big plus of the mod is less factories = less lag. Having larger individual crafts massively improves output.
Currently these factories fully beaconed with my MK4 beacon mod are outputing a huge amount. 1.2K purple/yellow science per factory per second for example. Over 60K science pm :D

I'm going to join in here and say that I agree with Danza, It's a significant limitation. The furnaces are very limited by this.