Pyro said:
They knew Goku was still alive. Why would he not have gotten stronger in the almost 2 years after Freeza?
Because he didn't spent those two years training. He went from Namek to Yadrat, then he spent a lot of time recovering from his injuries without a senzu bean, then he spent a lot of time trying to learn to transform into a SSJ at will and finally he decided to spent the rest of his time learning a new technique and travelling to the earth.
I mean, Goku said he didn't had much time to train, and Gohan compared Trunk's ki with his father in Namek. Him assuming his father would be much, much stronger and omitting this information makes no sense considering every time Goku increased his strength through training that didn't prevent the z-warriors to notice it and be amazed at it multiple times.
Pyro said:
We know Freeza can accurately guesstimate someone's power even though he lacks ki sensing abilities.
No, what Freezer can do is to notice someone is not fighting with all he's got, which is something anyone could do. This has nothing to do with sensing or guessing someone's hidden power, as it's proven by the fact that Freezer didn't expect Trunks to be a SSJ.
Pyro said:
He assumed with his power-up that he could take Goku alone, disregarding any power-up of Goku's own. How does that work if Trunks is the same power as Goku on Namek, and yet could own Freeza near effortlessly? I don't get it.
It works because Freezer's power was much lower than it was in Namek, as stated by Gohan himself. As it happens with a lot of characters after his ki has changed drastically, the only way for Freezer to know the extent of his new power would've been to test it. But Freezer isn't one to test or train, so he felt recovered, he felt he had better control of his ki -which if true would've meant he had powered up-, and rushed to earth to get his revenge.
The proof that Freezer didn't know the extent of his new power is that he spoke as if he still was stronger than his father:
http://mangalife.us/read-online/Dragon-Ball-chapter-137-index-2-page-3.html
But in reality he performed just at his father's level... while transformed into a form of power contention (both dodge at the same speed):
http://mangalife.us/read-online/Dragon-Ball-chapter-137-index-2-page-17.html
Pyro said:
We also have Trunks stating Goku is even greater than the rumors, which points to Goku being noticeably stronger than his Namek self since the rumors came from people close to Goku in the future.
This only means that Trunks didn't expect Goku to be as strong as he was, nothing more, nothing less. Firstly, he says "rumours" which means that it wasn't precise information. The rumours would probably only be Gohan complaining about Goku's death and him saying Goku was incredibly strong and that with his help beating the future androids would've been feasible at best.
He didn't know nothing about Vegeta, and I don't think they spent the whole time speaking of Goku while the androids were blasting the earth. Heck, even Trunks praising Goku trying to befriend him considering he was there expecting to learn a few tricks on how to defeat the androids in his timeline would be more reasonable than Trunks having exact information on Goku's ki at Namek and calling it "a rumor".
ahill1 said:
Trunks gives two fuck if Freeza powers up or no and everyone who comments on Freeza's defeat later on only mentions Trunks' capability of disposing of Freeza quickly, without giving any indication that the result would be different if Mecha Freeza were at full power.
The question is... why would they even give a fuck about that? We already knew Mecha's power was lower than in Namek through Gohan's comments about both Mecha and Trunk's powers, and also by the fact that a Goku that didn't had much time to train (and the few time he had he spent it learning the instant transmission) matched him in strength.
What is the point in Gohan, Goku or Piccolo to point that Freezer should've had more power than that? Freezer was dead, everyone was happy, end of the story.
Heck, Trunks lied about the future androids being that much stronger than him and if it wasn't because the androids from the present were much stronger he would've said nothing about it, and the same goes for Goku when he lied about his SSJ3 not being able to defeat the Fat Majin Bu. DB is a well written manga, it may have some flaws, but it has pretty realised characters that speak not only to describe a situation but also according to their personalities, their aims and what would make more sense to say. That's not to say there aren't forced scenes (Cell not remembering that Piccolo could regenerate his arm was a weak excuse to make character exposure), but all in all, it's pretty good in that regard.
I insist, we already knew what we needed to know, and there was no point on defending Freezer in front of Trunks. But since you mention it, when Krilin explains Goku about Cell's aim and they're all worried about the possibility of Cell becoming perfect Krilin says this:
Chapter: 366 (DBZ 172), P4.5-6
Kuririn: “Goku, tell us—This thing’s even more terrible than Freeza. Are you scared by that? Or excited?”
Goku: “…Both…”
Krilin felt Freezer at least up to his 50% of power, and he left the androids out of the question even when those androids were actively looking for Goku in order to kill him, and they were clearly stronger than Mecha Freezer or any SSJ was at that moment.