1. Aurora. She started off really well in Alpha Flight but quickly the character was ruined and I honestly dont think she ever fully recovered from that. Her appearances in X-Factor as part of the Brotherhood were disappointing - They just didn't do anything with her. She then reappeared in Alpha but contributed nothing. Her time on the X-Men was brief. Such a waste of a great character.
2. Emma Frost. Such a fantastic villain she was as the White Queen. Cunning and ruthless. I always wanted her relationship with Cyclops to be part of a much bigger story. Again proving his weakness for bad ladies (Maddy as the other example) The fact that they eventually just split up when he died was a bit on an anti-climax.
3. Spiral I think this character always worked better when she was independent of Mojo. The link to the Crimson Dawn was interesting as were her appearances in Excalibur. Her time on the Sisterhood was pretty flat and unexciting.
4. Psylocke - Biggest mistake ever, in my opinion, was separating the 2 again and having Betsy become Captain Britain. Totally ruined both characters. The mind switch happened and Revanche died and as far as I'm concerned that was that. The fact that she 'willed' herself a new body is ridiculous. If you apply that principle then the X-Team could revive Revanche and then we would effectively have 3 Psyloches. Betsy in Kwannan's body worked really well and defined the character.
Does anyone agree or disagree? Anyone any other examples?