Any of you old time readers will know my views on him from my reviews. Personally I don’t think he was a good choice from the beginning and he only has himself to blame for getting himself written out of the show.
For those of you new to this story, the short version is that Beltran made numerous nasty remarks in the press about his costars (particullary Kate Mulgrew and Jeri Ryan) and the writers. From that point on, each script featured less and less of him on screen. In fact, in the last season, you can watch nearly every episode and count his lines on one hand. And most of those amount to “We’re venting plasma” or “The shields are down.”