The forum is indeed the best place to submit feature requests. Either here, or you can email me directly, though it makes no difference either way. You have to remember that there are tens or even hundreds of thousands of Dorico users and only a handful of us working on the software. Although (thank goodness) feature requests are rarely unique to an individual user, nevertheless the sheer weight of requests that we receive and the fact that we can only work on a tiny, tiny proportion of them at any given time means that any individual user may be lucky to see even one of the things they have specifically requested addressed in a given release.
I’m sorry that to date we’ve not implemented anything that you have personally requested, but I hope you will nevertheless find many things in each new version that are also useful to you.
I believe Dorico’s engraving options for ties are pretty comprehensive and it should be possible to get results that are what you’re looking for in most cases, but if you have specific cases that don’t work well for you, please provide full details – ideally, a minimal project file containing just the problem or problems you’re seeing, with a clear explanation.