It's interesting that the journey from the Hoth system to Bespin was brought up, because I noticed that as being a glaring error for the first time when I watched the film this weekend.
The only in-story justification I can imagine is that the Imperial fleet was spread out among the local star systems looking for the Falcon, and that the Avenger made a hyperspace jump to the Anoat system to rendezvous with the Executor and the rest of the fleet for Captain Needa's apology, inadvertently taking the Falcon with her. Now that I think about it, this is supported by the dialogue as Leia asks Han where they are.
It's reasonable to assume that this part of the film elapses quite a bit of time, both because of Luke's training and because of how entrenched Vader is at Cloud City when the Falcon arrives, but to imagine that they somehow travelled from one star system to another at sublight speeds is a bit difficult to swallow, even in the fast-and-loose physics of Star Wars.
Regarding the speeds discussed in the films:
Hyperspace is never really canonically discussed beyond a few oblique references (the infamous “parsec” line, Han's dressing down of Luke during their escape from Mos Eisley), but it's clear that we can't take “.5 past light speed” to literally mean 1.5c, unless there is some unknown quirk to relativity that once you surpass the speed of light, your velocity increases by some exponential fashion.
There is something important about hyperspace that should be somewhat illuminating in this context as well: while all of the ships depicted have hyperdrive, nobody ever chases anybody through hyperspace. The one instance of this happening in the original trilogy is when the Death Star tracks the Falcon to Yavin, which was done by following a homing beacon.
We don't really know how hyperspace works, so while I agree that maybe a little more care might have been made in selecting the terms in the writing stage, as it stands, I feel it falls less in the “inconsistencies” and more into the “technology so advanced it looks like magic to us” arena.