Comfy UI is a mess and I never seem to have the GB of models, extensions, clips or whatever other voodoo a workflow demands . I actually use Forge UI. That's much more manageable.
Then you can add to that that the issue that all Stable Diffusion UI's have - 50 different people created their own flavour of a plugin on Github and half of them don't bother updating it anymore because they got a real job.
More seriously though...
With ComfyUI it is that you need to know a huge number of API's and, for want of a better description, the micro-workflows to use them. Those micro-workflows can be encapsulated just as we do a sub VI.
The main criticism I have with the ComfUI is its goups.
Why can't a group be represented as a control node? The groups are unrealised analogies to subVI's.
Where is my "Create Node" option?