Normally, candidates receive a bump in the polls after their conventions. There are two reasons to be skeptical that Trump will receive a significant bump, even though reviews of the speech seem net positive, if only because he passed a low bar, with length and darkness being the critiques. First, as I have been writing all along, more than any past nominees, both Trump and HRC are known quantities. The conventions are when voters might start to tune into the election, and while politics junkies (hi!) know who Sanders and Cruz are, nobody else does. Trump and HRC have been national figures for years, so the conventions change little, as will coverage of them. Hence, probably no significant bump. Second, the Democrats have theirs immediately after. This is all a wash.
As I've been saying all along, this campaign is sound and fury. HRC and Trump are known quantities, with little room for real movement in public opinion. HRC has maintained a narrow but consistent lead. That could change, but some event would have to intervene.