Pre-experimental tumble was good for only one thing, durdling with a shield. A dex based class (the group meant to be using it) trying to do that for long, even though blocking, is still going to end up dead. That is not what tumble was meant to be. And pretty much every example I have seen thus far from forum posters other than durdle tanking is also not what tumble was meant for but an alternative use players discovered that ended up being beneficial. Trust me. The developers did not intend for tumble to interupt bard animations or for some niche case of pulling mobs with it.
Experimental, however, was more like how tumble was supposed to function. But, while nifty and even fun, it didn't have much purpose. And then it sat, unfinished and unrefined. The mistake was leaving it like that for so long. The limits in place are limits that should have been imposed a long time ago. Perhaps not as strict as they are but there are limits to tumble now for the same reason you can't jump into the stratosphere. The world needs rules to both create and balance content around.
It's cool to point out buggy behavior with it. The implementation is not perfect and needs more work.
But just crying about not being able to use it the way it was being used, which was obvious to anyone looking at it objectively that it was not what the developers ever meant for it to be used for, or to try to nuke it from orbit in a "if I can't have it, no one can" moment is not feedback. It's more like a tantrum.