I agree with the OP that the drawing tools are in DIRE need of an update - well, a complete overhaul actually.
I moved away from Flash for drawing and animation a long, long time ago. I also found the drawing tools frustrating all those years ago. I animate and draw in other tools now. The thought of ever again being forced to draw in Flash actually scares me. Luckily enough I probably never have to. :-)
The drawing tools in Flash Animate are rather crappy compared to just about any other animation and drawing product on the market. Sorry to be so blunt - it is quite embarrassing when you look at what other animation products achieve nowadays. If you need improved drawing quality, switch drawing tools, and import your drawings into Flash Animate. But you mentioned you already are doing exactly that in Illustrator.
If you dislike that workflow, I would suggest it is time to switch animation tools, perhaps. For example, you could draw in a product with great drawing and painting tools which supports frame by frame animation (such as ClipStudio or Krita), and export the frames as images. Then import those frames in Flash. If you need vectors, batch convert those images to vector first, and then import.
Of course, the big news of the past few days in the animation world is that Toonz is about to go open source this week (26th). It's a $6000 industry level animation package as used by Studio Ghibli and the makers of Futurama. I am awaiting this with anticipation myself: it could be a game changer in the industry (especially for freelance animators and smaller studios). http://www.toonz.com/
For frame by frame animation Cacani is pretty awesome as well. It will tween drawings for you!
And the latest version of ClipStudio Paint EX now supports frame by frame animation too. ClipStudio's drawing tools are famous for their very high quality. I love the drawing feel in ClipStudio - one of the best in my opinion.
I have been playing around with the FbF animation tools, and they work very well.
If you hurry, you can still get ClipStudio Paint EX for only $87 - well worth the money.
Krita is also great for drawing and painting: the new (beta) versions sport full frame by frame animation as well - and it is very easy to use. And you get the full power of Krita's drawing and painting tools (outperforms Photoshop in that regard by a mile). Open source, and free!
(does not work that well on a Mac yet)
For completeness' sake, I ought to mention both TVPaint and ToonBoom as well. However, if Toonz turns out to be the "full monty", I really see no viable reason why a freelancer or indie animator would ever go with Toonboom (especially seeing that only ToonBoom Harmony includes nodes).
Herbert, thanks for the reply. I heard about Toonz. The problem with it, for me, is that it's just overkill and far more complicated compared to Flash. Flash always feels like a modern animation app should. Simple timeline. Simple tweening. Simple symbol library. Vectors. Color fill. Onionskins. That's about all I need. I'll look into it, of course, but Toonboom Harmony was a pain in the *** to try to learn. Toonz looks nearly the same.
Preran, there's no way just my complaint is going to motivate Adobe. I've been complaining about it for years. Many people have to stop putting up with this horrendous tool and let Adobe know together. I was hoping I could get that moving here.
OpenToonz is out! OpenToonz
A very different beast compared to Flash CC Animate, geared towards production-level feature length 2d animation. I have been playing around with it for the last two hours, and animating in it is actually quite simple. The timeline is quite different, as is the approach: it works with a classic x-sheet. But I found the timeline to be much simpler in use than Flash CC Animate. Just very different. And having access to a regular graph editor is heaven compared to Flash's version. And pretty good vector drawing tools! Even automated colour fill tools, as well as bones based IK animation.
OpenToonz is never going to replace Flash CC Animate for simple web animations in html, or interactive things. But for broadcast 2d animation I'd say anyone contemplating to continue to do so in Flash CC Animate, I strongly suggest to have a long and deep look at OpenToonz. There is a reason why Futurama and all of Studio Ghibli's films since Princess Mononoke have been using Toonz in their productions.
This is going to disrupt the 2d animation software market for indie animators and small studios, if I might hazard a guess. Flash is going to have a very difficult time keeping up with this - it just cannot at this level.
"We're working on improving the brush tool, use the feature request/Bug report, etc. etc. etc."
I've been using that procedure to post the brush tool issue each time Flash/Animate is update, I always obtain the same answer, but the brush tool just seem to get worse. I can't see any reason why that tool can be as good and fast like CS3, for instance. And drawing in another program to export the drawings to Flash is not the point. Seriously, that should be out of question for Adobe.
Towards the eternal "feature request/bug report" rhyme I also answer the same: most of the animators I know (nearly all of them) still stay in CS3 and don't dare to go beyond that version updating to a new version with worse workflow. Why? Because of the brush tool. As simple as that. To draw (therefore, to ANIMATE) is harder and harder each update, it's not your feeling, it's a fact.
Check this link with examples and images to see how Animate manage vector strokes. I appreciate your opinion about this.
Adobe Animate CC, brush tool worse than Flash.