Would a re-operation of a cataract surgery be a hassle or risky?

Question

ie to remove the implant and replacing a new one.

Answer 1

Just marginally more risky than having the surgery in the first place.
Infection and macular oedema are the principal but infrequent issues in both cases, and, rarely, damage to the lens capsule requiring an anterior chamber implant to be used (usually at a later date: another procedure).