@Finn dAbuzz,
When the Opposition Research goes into high gear, yes the unfavorables will go up-especially when you are far, far in advance of Election Day.
One thing that few people mention in the media is that issues that make a big difference far in advance of Election Day completely lose steam when Election Day nears and people start thinking about bread and butter issues. This is about the fourth election cycle where the immigration situation was early on seen as a huge problem, (ie, too much illegal immigration), and by Election Day nobody was talking about that and if anything, the issue shifts to "we don't want to piss off the Hispanic vote".
Apparently, the people who pay attention to the race early on are not indicative of the people who pay attention only after Labor Day and the conventions. In previous elections, the conventions were only over until shortly before Labor Day, so that period is considered as a unit. This year the conventions were both over five weeks before Election Day when people were still thinking about vacations and their "beach bodies", so we don't even know if this election campaign is in high gear even now.
Regardless, Trump has built his whole appeal around the anti-illegal immigration platform, and that issue has faded the last three election cycles as Election Day draws near. Indications are that he is trying to artfully back away gradually from it, but he's in so deep now that it is going to be hard to see how. Not surprisingly, as we near Election Day, Hillary's favorables have gone UP quite a bit and are nearly even now. The same cannot be said for her opponent. Here's the ABC News / Washington Post poll.
...............................Favorable ...............Unfavorable.............No opinion
8/1-4/16
....................48
.............................50
.............................2
7/11-14/16
.................42
............................54
.............................4