Only bad thing i see about that is: with heavies, you don't have many chances to compete at all.
So even if you don't build, but only plan one, you invest a LOT of time into that project, assume you could actually stand a chance (or at least survive the heat), and see bots picked where you know none of them would survive even half the time against yours. Be it because they are made of unsuitable materials, are in the wrong weight class or any stuff like that.

So while it's good for the Roboteers to have the show back, and it surely promotes the hobby, at the same time it limits possibilities and causes frustration.
Just imagine you've build something like Tombstone/ Last Rites. Now you want to apply to the show, and get a "sorry, we can't have you in there". Okay, sure, there are others, maybe better ones.

And then you see Obwalden Overlord, Creepy Crawlies, Sweeney Todd, Nuts and i forgot so many names...
Sure, all of them got something interesting, all of them got something the audience might want to see or something innovative, showing future possibilities. But at the same time... you could kill all of them even if they work together, and wouldn't even use the whole three minutes. And you weren't allowed to participate. And there is no other arena. So you either don't build the bot, or if you already did, quiet likely wasted a lot of money into it. Because if one day you may participate, chances are there is already better tech on the market.
So before starting a heavy project, people think twice or even more. And as long as they do so, there won't be another arena for heavies around anytime soon... It's quiet expensive and big after all, so there'd have to be a big demand for one.

So actually making qualification fights, maybe with a youtube-minishow to it (you can make money out of that stuff, too) would be way better in my opinion. Maybe reserve one place per heat for "interesting" "innovative" and other bots who else would never be seen in the final show to spice things up. That'd leave 3 qualified and 1 wildcard per heat, and about everybody who build a bot get to use it at least once.

Building is fun in itself, but at least for me... if i finished something, i want to use it, too.