Did you mean EiffelStudio ? What was the painpoint at the time ?
I've only played with it 20+ years ago (a colleague was one of the few practitioner) and I don't remember EiffelStudio being _that_ terrible (it has a class browser that was not that much more horrible than Eclipse at the time) - but again, I only dabbled.
Now, I have to agree that the way they market the IDE as the best thing since bread came baked is kinda cringy..
It was whatever they were shipping in the early 1990s, CLI tools. It cross-compiled to mangled C++ which made it un-debuggable outside of inserting print statements, compile turnaround for even a small program was 20 minutes on a reasonably speedy DECstation (now pair this with the debugging comment), it used some node-locked licensing scheme where, when the compiler crashed, which it did a lot, it left the lock active so someone with root access had to come in and remove it, and lots, lots more that I can't remember. It's a pity camera phones didn't exist back then or I'd have a photo of a whiteboard with a drawing of the Eiffel tower, broken in half in the middle, and a figure in a noose labelled "Meyer himself" hanging from it.
Nice language, but seriously cursed by unusable tooling.