2) "It is likely" isn't good enough. You're hypothesizing. Could they have found them? Maybe. Could they have not found them? Maybe. All we know is they didn't find the bombers but instead slandered a number of individuals and family names in the process.
3) I'm not sure what your background is but I like to believe that our federal law enforcement (FBI, Police, SWAT Teams, etc.), while not perfect, is pretty well-trained and collectively has thousands upon thousand of YEARS MORE experience than I do in collecting evidence, timing its release, and generally fighting crime. As such, I imagine the timed release was not to delay or elongate the process but was very intentional.
I do agree with you that it seemed to take longer than is desirable to find the suspects (especially since once they were found, one got away) but a "better system" is by no means the hive mind of untrained "armchair investigators."
Perhaps in the future there will be a way to crowd source information but the responses of Reddit 4chan, and yes, even some here on HN were well-intentioned but harmful. An apology from Reddit seems perfectly acceptable.
[1]http://en.wikipedia.org/wiki/Witch-hunt#Metaphorical_usage