The Targaryens historically aren't nice people. Slavery, genocide, polygamy, incest... all commonplace. Viserys building a model and talking about old Valyria would be like a modern-day German talking about the good old days in 1930s Berlin. I have no issues with how Danerys ended up on GOT, the major problem was there was zero development or buildup. She went crazy in a matter of five minutes.