TAIPEI, Taiwan — It seems blind activist lawyer Chen Guangcheng is on his way from being a mere brutally repressed dissident to being a full-blown political exile. But while his immediate safety, and that of his wife, looks to be assured, other dissidents who have been in his shoes caution him about the difficult road ahead. Be careful what you wish for, is the general sentiment among a group of prominent Tiananmen protest leaders — who were either exiled in US-brokered deals following lengthy prison terms or escaped the country following the army led-massacre in 1989. From experience, they say, once you leave China, it’s pretty tough to get back in.