That's not a plot hole
Frieza getting as strong as Goku SSJ God within only 4 months only by spanking Tagoma and Tagoma becoming as strong as a imperfect Cell only by serving as a punchbag for 4 months... if we consider this, then both would be stronger than Whis if they trained that way ever since Frieza destroyed the planet Vegeta; Gohan's weakness by itself is another plothole;
What plot holes are there? And beerus retcon?
Goku should step back, right now DBS seems to be pure fanservice since Toriyama is playing at the safezone (Goku time just like DBGT). For real, the plotholes, terrible animations, Beerus retcon and Gohan are killing the series for me at the point of refusing myself on considering DBS canon.
Well, I trully hope that those inconsistencies dies together with Frieza, but considering the actual Super direction, then it's more than obvious that the Beerus' team will win the tournament of the next arc...
Well, the annoying retcons, Beerus is behind the planet Vegeta destruction, he is also behind the imprisonment of the Elder Kaiyo in the Z sword, which has another plothole:
It's like AT is desperately trying to introduce beerus as a long time DBZ character, but seems like he need to rewatch his own series.
News flash: Beerus is the responsible for the zombie apocalypse in The Walking Dead!1!!
A plot hole is something that's left unanswered and unexplained, these are the exact opposite of it.
A) there's something called a limit, both freeza and tagoma hit their limit after they drew out every last drop of latent power they had. Toriyama even went on to say that basically no matter WHAT freeza does, he'll always be below beerus
B) Gohan's weakness isn't a plot hole, it's explained. He can access his mystic power, but because of not training, his body can't handle all of it, so he has to access it through ssj.
C) beerus wasn't behind planet vegeta's destruction, as freeza makes it clear that he's destroying it for himself in DB minus. All that's known (IIRC) is that he was in favor of it.
D) it's annoying, but it's not a plot hole. Elder Kai was sealed 75 million years before the beginning of the series, beerus most likely wouldn't be as powerful as he is now (which he's been for at least 900 years)
TLDR; all of those aren't plot holes, as they have an explanation to it, the beerus retcons were a bit annoying though
These are plot holes:
A) There is no reasonable logic behind Frieza and Tagoma (mainly Frieza) getting so strong in a short amount of time but pure fanservice. If he were becoming as strong as Gohan and only both fighting in the final match without Goku's time, then the arc would make more sense, but this isn't the case here.
B) Gohan slacked much more in the timespan from the Cell games to Buu saga and he haven't got Klebitz'd for this, then he slack for something like 5 years and he suddenly turns itself into a saiyajin version of Yamcha.
C) Beerus told Frieza to destroy the planet Vegeta, it's retconed in Super. So all that awesome fear of the legendary super saiyajin went to the trash bin.
D) Makes some sense, but let's hope that they don't try to retcon Beerus in the Buu's hibernation too since he is also retconed for being the "meteor" that killed most of the dinnosaurs on the earth. Perhaps he's Kal'el's daddy too.