Yes! This is a big problem!
However it seems, the change is reverted. Just today /model gives 3 options instead of 4:
│ 1. Default (recommended) Use the default model (currently Sonnet 4) · $3/$15 per Mtok │
│ 2. Opus Opus 4.1 for complex tasks · $15/$75 per Mtok │
│ 3. Opus Plan Mode Use Opus 4.1 in plan mode, Sonnet 4 otherwise