You cannot realistically compare Procreate with Artstudio Pro in this way, because the former is lacking a serious number of features that Artstudio Pro long has. And I’d argue if Procreate had all these features, I personally would find their (Procreates) approach of hiding many options into the UI or just behind gestures, much more confusing.
ASP has a clear way of managing its options from the burger menu (the three lines on the top left). This shows the menu bar from which you can reach all of the options, filters etc. in a clearly structured way, which additional shares a similar structure to desktop apps like Photoshop or Clip studio etc., so for people coming from such apps, this approach already feels very familiar.
Additionally, you can assign every single thing from this menu bar, to either your top toolbar (that is freely customizable and accessible through the three dots "..."), the quick menu, or keyboard shortcuts. This way all of the things you frequently need/use, can be accessed super quickly.
And whenever you’re using any of the many tools, you can simply press the “2 sliders button” on the bottom left, to bring up a bunch of different options for this specific tool. It’s simple to understand.
Artstudio Pro is made for people who need much more options than Procreate or most other apps for iPad currently offer. And they managed to do so, while still keeping a clean looking UI, made specifically with iPad in mind. So even if you wouldn’t need all of those additional features, you can always just customize the UI to be/look as simple or as complicated as it fits to your personal needs.
So obviously it does have a slightly bigger learning curve than Procreate, especially if you never used any desktop level drawing apps before. But it’s still far from being overly complicated, and far below Photoshops and co. learning curves, but while still offering most of the same functionality and I'd argue even better user experience to the way many tools work inside ASP compared to Photoshop.
For example Elastify, works so much smoother and simpler in ASP than in PS. A simple native perspective tool or the option to clear selections over multiple layers, the fact that empty layers are marked as such, and that you can clearly see which filters are active on the layers etc., are just a few minor examples of how ASP exceeds in terms of UI/UX compared to desktop apps like PS.
So once you understand the overall way the app is organized, it becomes very easy and intuitive to work with. I truly believe that the lucky clan team did a very good job on keeping the UI simple, yet providing so much professional options and tools. But it is my all time favorite drawing app in terms of UI and functionality ever, so I’m definitely a bit biased.
However, the app definitely could improve in certain parts of it, and in fact it does continuously improve, and the amazing part is, that the developers always take their user feedback very seriously into consideration and bring new improved updates constantly, despite only being a small team. ASP is definitely far from needing a complete overhaul of the UI, anywhere in the near future. Quite the opposite, the UI keeps getting better with each new update they release.
And I’ve also seen Borodantes videos of Artstudio Pro, but they are already outdated by now (his last review is over a year old), and most (if not all) of the “problem” things he addressed in his videos, have since long been fixed.
And to answer your question, you can find the Liquify/Elastify tool under the Burger Menu > Filters > Elastify. In order to access it with a single press, just put it into your quick menu, top toolbar, or assign a keyboard shortcut to it.
Also, lucky clan just recently published a user manual (https://www.luckyclan.com/artstudiopro/artstudio_pro_manual.pdf
), so if you’re struggling a lot, this will be a good place to start. And people on this forum are also always willing to answer your questions.
TLDR; And if ASP is still not for you, after all of that, that’s fine too. But to then go on the forum, and telling the developers they should overhaul their whole UI because you don’t like it, without even giving any real constructive solutions or suggestions, is not very helpful at all.