This trade is hard to evaluate.
Taken as it stands, 1 year of Smart and 1 year of Thompson for 1 year of Dragic and 2 years of Herro, I make the trade. Not happy about losing Smart but for one year, we are a little better and then we get Herro for 2 years plus the RFA status over Smart being UFA.
Now if your assumption is that we are going to sign Smart to a reasonable contract to keep him, then not so sure. I like Smart long term over Herro (assume Thompson and Dragic are "one and done" and not figuring into the long term calculation).