The implicit stench of Neelix technically being a pedo with Kes despite the actress' actual "human age" was something difficult to shake. Neelix's less-than-admirable behavior throughout the series, especially as it applied to Kes and his several over-the-top conflicts with the other members of the crew should have earned him a one-way ticket out the airlock early on. This would have also had the pleasant byproduct of preventing the Tuvix incident from ever having occurred in the first place.