Gotenks funnily enough could use it better than Goku did, and Goku also says he's not used to the form too.
Problem with the form is that it's hard to master it, but there's a possibility that mastering it can work, kinda like how Goku and Gohan managed to remove any drawback SS1 had.
Toriyama claims it's the case, but as far as what's actually shown, SS2 is just "SS1, but better in every way" even if we only talk about the original manga.SSJ2 is probably similar in concept but because it's not using the same amount of power, it's less of a strain.
Honestly, Beerus easily overcoming it isn't a weakness of SS3 itself, just that Beerus is that monstrously strong.The whole point of SSJ God and SSJ Blue was that they were forms that didn't burden the body with excessive energy strain to maintain them.
It's worth noting that when Goku goes SSJ 3 each time there is a problem. The first time it saps his time on Earth, the second time against Kid Boo he loses all of his energy and can't win the fight. Then depending on the continuity you want to use in GT his kid body can't maintain it, and in Super, Beerus just easily overcomes it.
And hell, going by the few times SS3 is used in Super, its stamina drain problem seems to have been toned down a lot, considering how using it for only like a minute against fat Boo even while dead made Goku super tired, but his fight against Beerus and the sparring match against Trunks had him being fine afterwards.
That plot point was stupid lol.
In RoF, Goku and Vegeta talk shit about Freeza's Golden form, saying that the form wastes too much stamina, and then Toyotaro decides to show that Blue is even worse with the stamina drain? Come on...