Let's face it, nerfing SM EC has a massive consequence, people who can clear SM EC will not have as good quality practice for HM EC. By making the mechanics in SM EC so much easier (and there was a big difference to begin with) they've changed it from a way to practice for HM EC to just another easy op.
Before it was more mechanic heavy than EV/KP on any difficulty, now it's just a gear check
So with the changes the new difficulty would go like this
1. SM EV
2. SM KP
3. SM EC
4. HM EV
5. HM KP
6. SM TFB
7. NiM EV
8. NiM KP
9. HM EC
10. HM TFB
Now does that seem like a good idea to you?
There's 5 Operations between SM EC and HM EC. That's going to hurt people who are just starting out and haven't done HM EC yet.