Two points:
1. Any evidence, classified or not, would not be made available to the public during an active investigation.
2. If there was absolutely nothing then why would this investigation be closing in on a year now?
I don't really think that there was actual collusion between Trump and Russia... Perhaps Flynn told the Russias not to sweat the sanctions Obama imposed, that may or may not be illegal, I dont know the law well enough to judge that right now... I do know there is some shady business going on, there are too many lies not to think so. Whether it was just political posturing in search for good PR, or something real going on, is yet to be determined.
Again, based on the facts in evidence, there is not one piece of evidence to support any part of Obama's Russia hoax, not even the charge that the Russian government hacked the DNC server. The argument that the facts can't be revealed because of national security reasons or because it is an ongoing investigation is not credible; it raise the question of why the Obama administration worked so hard to make all these claims public and worked so hard to persuade the public they were true if it couldn't provide any facts to support them?
The fact, as you have observed, that this investigation has been going on for nearly a year and yet not one fact has been put in evidence to support any part of Obama's Russia hoax and not one person has been officially charged with any wrongdoing leads to only one reasonable conclusion: the whole Russia thing was invented by the Obama administration to try to influence the election in favor of Clinton and is now being used by the Democratic leadership to try to rally its fractured base and to try to obstruct the Trump administration, or as President Trump puts it, it is all fake news.
No matter how cynical you may consider yourself to be about politics and politicians it is still shocking to consider that the Obama administration spent all of this time and energy, compromised the integrity of so many institutions of government, perhaps committed felonies or suborned others to commit felonies all to promote a purely fictitious narrative about Russia and the election.