In December of 2014 I was asked a pre-emptive question about this.
Things have changed.
I'm very excited about this movie having seen the latest trailer. Jared Leto's Joker is looking mighty interesting, and the tone seems fun.
Most important is the director.
David Ayer has been fucking killing it. End of Watch in 2012 and Fury in 2014 were both excellent. What's most encouraging is that the people at DC would think to hire this guy at all. He's clearly the sort of director that was going to bring his own vision. This bodes well for the DC movies if they leave directors alone to do what they do best, completing their concepts without having to adhere to any strict guidelines. I don't know if this is the case, but its looking good.
I don't expect Suicide Squad to live up to recent Marvel fair, but that doesn't mean it can't be a good time, and help push the DC universe along in a positive fashion. Seems like every time DC starts up, they have a bomb that kills everything. For that matter, Bats vs Supes better be pretty frigging good or they could find themselves cancelling a whole lot of big plans.
Short Answer: Too bad they lost Tom Hardy. That would've been nuts.